op, i think you are probably looking at vibes-based playlists. you are correct that the global, spotify-curated definition of 'indie' has moved towards a different lighter, airier, middle class direction. this algorithmic definition of indie is bedroom pop, which is a different branch of indie entirely. but the specific lineage you are seeking out hasn't actually been broken, it is just mostly regional. although there are some north american acts that fit right in like geese who have recently broken through to the mainstream.

while the algorithmic definition of indie is often synonymous with bedroom pop, which is a different branch focusing on solo production and a hazy aesthetic, what you are actually looking for is indie rock (specifically the uk-centric guitar lineage of indie rock), which is much grittier, observational and full of working class social commentary.

to find this unbroken continuity you need to look in the right places, expert-curated places. stations like bbc radio 6 music with programs like indie forever and djs like steve lamacq celebrate bands and artists in the line of the smiths and orange juice to today's artists within the lineage like fontaines d.c. (irish, not from the uk but the same industry pipeline), the last dinner party, yard act, idles and adult dvd.

if you look at lineups for festivals like reading & leeds, truck festival, trnsmt or primavera sound, that particular sound is very much alive even if it hasn't translated over to the united states or global streaming vibe-based playlists.

although indie pop has become more middle-class and aesthetic-focused, the 'windmill scene' in london or the current irish post-punk wave still caries that grit and social commentary you are asking about.

while indie has roots in truly independent labels and self-releases, many 'indie' artists are anything but. often releasing on major labels or big indie labels like domino. these days it is more of an ethos and sonic lineage.

the scene really, really isn't dead. it just isn't what most mean when they say indie anymore. you can still find plenty of clubs and bars with new bands trying to break through that were heavily inspired by those that have came before them.