1 gallon is only 4 litres, this is an extraordinarily small tank.
Would be cruel for even a single betta splenden to be in this tank, never mind anything other fish specie.
Be a bit like trying to put a Great Dane into a cat cage and expect it to be fine.
Even small species of fish like chilli rasboras will not do well in this small tank, as well as any other small species for that matter need space to swim in, this is an important factor for the well-being for fish.
I would always maintain that the minimum sized tank for Chilli rasboras is to be a 10 gallon tank, that’s 10 times the size of your tank.
www.seriouslyfish.com
And for a betta splenden the minimum tank size being a 5 gallon tank.
The reason your shrimp died previously is probably because there’s no filter or flow going into that little tank as well as it being unlikely to be cycled.
Shrimps require an established tank to flourish in and that means a cycled tank at the very least.
Even though this is a very small tank it does mean you may be able to keep a couple of shrimps and maybe a small snail or two with some plants, a simple sponge filter or one of those tiny penn plax filters with a small air pump will do the job nicely of filtering the tank and aerating the water column.
And yes, some substrate would be good not least for the plants but for the snail/s and shrimps too.
But due to the small amount of water, you have to keep a very close eye on the water parameters as there is very little, if any, room for margin of error.
Probably best to keep that tank as a plants only tank or better yet get a larger tank.
I’ve no idea why stores sell these “tanks” to people probably knowing full well it’s pretty much a useless tank for fish, pure profit or greed of the seller is the point imho.
Some of these YouTube folks who do these videos are even worse than some of these stores selling these tanks to be blunt!
Sorry these are probably not what you want to hear but even experienced keeper would think twice before even considering buying one of these tanks.
Edit - you posted your last message just before I was finished and am glad you are aware but I will still keep my post up just in case other folks who may be considering doing something like this may learn something at least.