If you have lots of concurrent writes SQLite isn't the right solution. For concurrent reads it's fine.
SQLite also isn't a network database out-of-the-box. If you want to be able to access it over the network you need to solve that separately.
(Don't try and use NFS. https://sqlite.org/howtocorrupt.html#_filesystems_with_broke... )
That becomes an instant problem if users ever write to your database. You can't duplicate the environment unless it's read-only.
And even if the database is read-only for users, the fact that every time you update it you need to redeploy the database to every client, is pretty annoying.
That's why it's usually better to start with Postgres or MySQL. A single source of truth for data makes everything vastly easier.
If you have a read-heavy app (99% of saas) that runs on one server and dont have millions of users then sqlite is a great option.
SQLite is designed for one local client at a time. Client-server relational databases are designed for many clients at a time.