I've been in a number of play-by-post campaigns over the years. Discord has made it incredibly easy to do.

It’s slow as heck but discord has a free built in die roller app so really the only thing you need is discord. (Usually the issue with playing D&D via text is die rolling)

Look into something archaic called "Mushes/Muds". It's pure text based roleplay in a variety of genres.

Discord is the way to go. You can play via voice chat or through text channels. It's been excellent for an introverted agoraphobe like myself!

The TTRPG Alice Is Missing is played entirely via text and is emotional and intense and amazing. It’s just a one shot, but you could play it a few times. It is a completely narrative heavy roleplay game though, so if you’re looking for combat or d&dlike mechanics, this probably isn’t what you want.

Forum based play-by-post! My preferred site is Myth-Weavers.com :)

Discord!

I am co-storyteller for a Vampire the Masquerade 5E game set in Kansas City that recently added mages and werewolves as PCs. We are newbie friendly and always recruiting, if you are interested. https://discord.gg/n36nGp7w

The RPG Club specifically GM Keenan Halpin has a play by post campaign. You can find him on the website.

Play by post is the style of campaign you want, often abbreviated to pbp. There is also an excellent texting based ttrpg called Alice is Missing that you might want to check out as well.