What about shared hosting?
At moment we can install flarum with pockethold or use ssh to do it!!
At my point of view, i am frontend developer and i work with a lot of clients, hostings and so on as i am freelancer!
if the webhost dont have php 7.4 and ssh aka console... dont even worth be with them! Thats a fact!
php 5.X is slow, really slow
ftp is getting old, sftp still okay, ssh is purely safe and easy!
for example my own shared hosting, i dont have 2GB of physical memory so i cant update extensions with composer, bcs composer uses more than 1 GB
i just install it via pockethold and then, run a flarum installation locally, update extensions and everything i need, go on ftp, sftp, ssh and upload the vendor folder, replace with the vendor folder in the shared hosting, and voila, done!
if the hosting have ssh (normally you have 2 types SSH icon to grant access to ssh and CONSOLE)
console you can run right on the browser, no need to logins, just need to dir to locate yourself, cd folder/folder
run composer commands
if i agree with flarum have some sort of instalation like wordpress or scripts in sofctaculous? yes would be good, but pockethold do that already!