I hate CHECKPOINTS! gamebreaker etc.

For me personally, the only time checkpoints are annoying is when it saves your progress in such a way that you can't go back to a previous place when you missed something. This doesn't just affect games with checkpoints though - it affects many games that don't allow backtracking, etc. A lot of games get around this supposed issue by allowing you to revisit chapters or levels, or having NG+, whereby the things you had previously found or received are retained.

As for Alan Wake, I don't recall any time that checkpoints were an issue for me. I'm the sort of person who would rather have an autosave/checkpoint system, than forget to manually save, and have to re-do an hour or so of game just cos I died from being IMMERSED and FORGETTING...

Each to their own ;)

When you don't have the time to play for a long session at once, badly placed save points can literaly mean a game you can't play.

Depends on the game. Alan Wake - what did you expect ? It's so linear and it has so many autosaves that theres literally no point in having manual saves.. It would be cool if it had, but it's hardly mandatory for a game that basically doesnt have open world. (I hardly count the road sections as open world)

As for other games. All I can say - If I play a game for several hours and it crashes and I lose all the progress because it didnt have autosave, I'm sure not playing it again for a long time. In the best case scenario for me - it has autosaves regularly and I can save manually as well if theres a need for that.

And considering that these days everyone is strapped for time, having some kind of milestones to which to stop playing the game is great. It has been many times useful for me to get to a checkpoint where I know that I can surely close the game as I have completed some specific part of the game and I dont want to play more at that time

Save whenever you want is awful! Sucks all the suspense out of a game and makes it a chore to play. The same goes for frequent, not punishing enough checkpoints. Modern games got it all wrong at some point It's now a matter of WHEN I complete the game, not IF I will ever be good enough to complete it. It's very ironic that it's supposedly boring to replay the same levels over and over again, and you get those huge games with extremely repetitive gameplay instead.

It must be hard for developers to make decisions about checkpoints since no solution is perfect IMO. As you say they can be immersion breaking and it can feel like a bit of a spoiler that something big is coming up. Depending on the game though it can add tension similar to boss music and at least you get time to prepare.

What I really don't like though is when auto-saves are subtle and you aren't sure when the last one was, especially in games where they are less frequent. My partner is comfiest playing his ps4 in bed but sometimes if I want to go to bed early or he is up late it can be a pain when he has no clue if he can save soon or not and of course as a gamer myself I don't want him quitting mid-mission. Some games really don't respect your time though so it can mean a lot of waiting around for me (if only they made silent button gamepads!)

Also it took me a while to get used to auto-saves when they started appearing games - I was like "nooo don't just randomly save on me, what if I missed something!" and here is where well designed games can really shine - if you are able to backtrack in a way that doesn't feel tedious but instead more of a puzzle then that can be really satisfying. Personally for me (especially because I have chronic fatigue/illness) I much prefer being able to save when I want, I like to make multiple save files so if I did mess up badly then I have multiple "checkpoints" to choose from. I can see how this ruins the challenge for many people though.

Being able to save whenever has its own issues though! There's a time I still laugh about to this day - in Skyrim when you first go to the mage college then leave through the door to the courtyard there was a surprise dragon right in my face. Well I panic-saved, just as it was blasting me with fire and I instantly died. Cue a groundhog-day scenario with me desperately trying to get out of the way as soon as I reloaded and dying over and over while my partner is doubled over laughing. Almost resigned myself to loading an earlier save but I managed to dodge it in the end! 🤣

I understand what you mean, it's definitely an interesting design challenge. I am not a big fan of checkpoints either, because they just remind me that I am playing a video game. So basically they break immersion, yes.
I think organic checkpoints on the other hand are great. When they are intergated into the world in some thematic way. An example would be Dark Souls where bonfires are checkpoints, yes, but they aren't UI prompts and lighting them is a great fit for the style and tone of the game. I also liked Borderlands 2's system. There, checkpoints are basically revive stations that thematically fit the game world, if I recall correctly.
Intereating topic definitely!

checkpoints and regenerating life, two cheap ways to manage balance in a game.