I highly recommend everyone to use Zotero. Their original marketing as being 'for academics' is entirely wrong and it is a first-in-class bookmark/knowledge manager.
There are many software recommendations that seem sort of hype-y: Obsidian, Notion, Keybase, etc. Zotero is not that and is a daily driver for me for years. It has also replaced Calibre for me although YMMV there.
I second the recommendation for Zotero, especially if you find yourself buried under PDFs. Two things make it very useful for me. First, it organizes my PDFs and lets me search them, instead of manually searching through directories. Second, it has an OCR plugin, so I can OCR old PDFs and search the text.
I haven't used Zotero in anger for a few years and can't get to my laptop right now to verify. But I used to rely on automatic exports to a folder that I sync'd elsewhere. Never used a paid Zotero subscription, never "self-hosted" it, and had many gigs of data (including PDF attachments) working fine for years.
I used "better bibtex" (?) to ensure files were reliably renamed and moved to an appropriate folder, all automatically.
A real set-and-forget setup that ran without hitch for years.
uh oh - didn't realize sync was paid (stupidly). apparently i am at 99.6% of the free tier
now i'm interested in the answer to your question - i have my own machine running 24/7 that i would love to use. i like the software enough that maybe i'd pay/donate
There are many software recommendations that seem sort of hype-y: Obsidian, Notion, Keybase, etc. Zotero is not that and is a daily driver for me for years. It has also replaced Calibre for me although YMMV there.