How to group songs from different albums into one album?

Hi community,
I am fairly new to this community but know quite a bit about mp3tag, however I need your help now.
My problem is:
I have a few songs on my PC which are from different artists and different albums (mostly singles) and to keep my music collection on my phone organized and since most of them are singles, I want to group them together in Albums so my music player doesn't show "unknown album" or similar nor countless albums with the names of the artists which looks really messy in my album list.
So far so good but to get to the point:
e.g. I have some songs which are "pretty chill" and I want to group them to one album called "chill" or whatever. Well the problem is, now every single song in this album has the same cover, of the first song (starting from A) in it (I removed the tracknumbers btw), even though it took me hours to find a high-res cover for every single one and embed them in the files (don't like to mess around with separate jpg files) and also made sure that I deleted all folder.jpgs and whatnot. I know I could go with genres or playlists but my preferred music players doesn't have a genre tab for whatever reason and I'd still have to mess with wacky album names when looking for an actual album or just browse my collection.
Is there any way I can have albums which don't share one album cover? Is this a general "feature" or is it just the music player assuming that, since it is one album, they all should have the same picture?
My music player doesn't have a lot of options (so I can't change anything specific concerning covers or similar) but I like it's DFX and hope I can find a way to fix it

MP3tag is not a "media library manager" it writes tags and can embed images in the files but it does not organise or group them into 'albums'.

You can set the album tag to whatever you want using mp3tag but it is your music player that does the sorting.

You have to fill the following fields for all the files that should belong to one album:
ALBUMARTIST
ALBUM
YEAR

Each field should be filled with the same contents as the corresponding field of the other tracks.
It is not necessary to have the same cover in each file - but it is up to the player whether he shows just one for all or the separate ones.

There are actions to copy the contents of one field to another, e.g. if you want to keep singles as singles then you can easily copy the contents of TITLE to ALBUM.
The same applies to ARTIST and ALBUMARTIST.

Unless you have a separate copy of your collection to synchronize with the mobile player, I would not mess around with the already distinguished data only to make it look nice on a player. Once you have lost information (which you do if you replace the differentiated info with the same for all), it is hard to get it back.