Looking for 90's underground death/doom gems (demos or albums) in the style of Mythic, Disembowelment, Decomposed, Winter.
Open to really lofi shit and funeral doom sounds too

I'll give you a few of my favourites, you may know them already:

Thy Grief Eternal (pre-Electric Wizard)
https://youtu.be/4MMJRZdDKP0
https://youtu.be/POFMyO0ah3o

Eve Of Mourning (the Illinios band, not the other one). Vocals are a bit more gothic, but it does border on doom/death.
https://youtu.be/OFDNdphgMC0

Church of Misery (the US one, not the more famous Jap band) "Sorrows Of The Moon" demo. Sadly not currently on YT, I might have to change that soon.

Edit: I've uploaded the Church of Misery demo:
https://youtu.be/O8DPt5f7bC8

I'm going to assume you're already familiar with Anathema's and Paradise Lost's early early stuff?

I was familiar with Thy Grief Eternal but haven't heard the other two. The Church of Misery demo is really great, I loved it! Thank you!

Cool, glad you enjoyed it. There's an album too (recorded in 93 but only released in 2012), personally I prefer the demo.
https://razorbackrecords.bandcamp.com/a ... f-mourning

Do you know Godsend's 1992 demo (also known as "Starfall" demo)? That might be of interest to you. May be not enough of a death influence in there though.
https://youtu.be/Av1PmXmuQ1k