I read "free" and "less annoying"? Think about it again.
They try to get onto your personal nerves until you finally give up and buy this Super monthly/yearly subscription.
Like with Busuu where further lessons are now suddenly LOCKED after the Web/IOS recent redesign until you A) either buy their Premium (Plus) - Non-lifetime - yearly auto-renewing subscription (you first need to unsubscribe on your Paypal account to make the Busuu Web Cancel button work) or you really complete the current/previous writing/speaking community lesson exercises.
Their broken part1 and part2 exercise code in lesson 29 of A2 French meant I couldn't continue for weeks with lost part1 progress until I finally figured out the workaround how to skip over.
So they now force you into doing them which is also the case on the old Android app with a Non-Premium account which has not seen this redesign yet.
Die Qual der Wahl.
If I had to click the "Pay with Gems" button every time I start a new League challenge or a Legendary challenge I just would be annoyed.
So they - whoever took over and has been "back engineering" all this better written (old) code by corrupting more and more of the original Duolingo idea with new stuff including childish UI looks, overfilled cartoon characters and crazy animations - surely don't want to make it "too easy" to get away or offer too many things for free, not anymore.
Hope I haven't formulated this too hard as I'm translating my direct German thoughts in my head into English as my second language.
But to me it often looks like a complete different business analyst or developer team took over now (like once the original product is sold to someone else who has other priorities) since a while driven by tight requirements / rules.
My wish: I want the more professional classic Web UI theme from 2016/17 back!
The new snake (Web) UI is a mess and it takes some time to create all the uBlock Origin cosmetic filters to remove the dancing cartoon elements.
Unfortunately, I can't remove them from the lessons on the Android app (old tree 5.52.5).
No SuperPlatinum membership option is available to remove them all and switch back to an adult more neutral theme.
Your wish for a not terminating (new) lesson is of course legit and the immediate termination makes zero sense.
In my opinion, binging is just an excuse from staff and health/hearts doesn't make that much sense on the new path or a crown level system where you're automatically forced going into higher levels as another dimension while the difficulty increases
(typing, target translations, full sentence construction, longer sentences, presenting since summer 2018 previously suspended sentences with a higher user error rate and several user reports as they moved up the crowns chain) and not when you're truly ready.
Before you could just hit the Practice button and stay on the current crown level. Pre-crown era had the Re-strengthen button too.
It's somehow laughable that Duolingo just terminates your current session and doesn't even show you the correction / answer solution or giving you access to sentence discussion.
I hope I remember correctly as I'm running on "unlimited hearts" since a longer time and will probably have to retest what I wrote here for the next days and weeks.
But basically it was the same issue with timed practice exercises on the Web until they removed them.
Full stop if time was up; you couldn't read your own typed answer if it was right or wrong and you never got the needed correction.
Of course time was always too short with all the long and ultra complex Portuguese sentences.
Like it is with the Lightning rounds in Leagues were they robbed over 20,000 Gems until I found out how to complete the round on Android without any refills.
It's hardly possible to go over the penultimate Xp point.
Same with Ramp Up challenges and the third or second middle or end rounds.
Another issue is the lack of accepted synonyms and alternative answers in the sentence DB in the German from English (Cefr) course and other courses which maintenance and clearing of error reports have been neglected for too long.
It seems by intent Duolingo staff releases broken code just to annoy its user base and NEVER have them succeed to finish their exercises?!
They make sure that you fall over, to generate full stops to create a hole in your purse so money can fall through, not only once but monthly/yearly, but not because you liked the business product idea and some dedicated features and wanting to honestly support them
(or more the former course contributor team and forum course moderators who patiently answered questions and tried to clear beginner doubts - that was the main selling point for me to get lesson assistance and I don't know why I can't save a super complicated sentence for later review and discuss it and grammar and alternative solutions from sentence discussion with a real linguistic teacher).
More over: I can't even read the quite small lesson text on Chrome Dev on a 6.67" Android smartphone as text scaling / zooming doesn't work with the horrible cartoon characters on the lesson screen.
How could functional testers miss this??
So I have to use Firefox (FF) Nightly in debug mode, manually enter a collection_id to get back addons support on mobile, remove all cartoon elements with "uBlock Origin" cosmetic filter rules and set FF text scaling (Accessibility) fomt size to 155%.
There is a new Chrome Dev Zoom flag which you can activate and restart the mobile browser but it hardly worked with the messed up Duolingo Web code.
Chrome mobile Zoom support also was broken on their community forums.
TL;DR:
As you said it already: Create a school classroom as a teacher as a workable workaround and then you don't have to overthink intentially bad code design and why you're always kicked out of this and that or why no affordable lifetime option exists.