A question with probably not lot of answers but definitely a lot of opinions :-). I’m afraid it’s a bit like ‘how long is a piece of string?’
My first thing would have a bit of ‘clear out’ of the 0ne you have and see if that makes a big enough difference to the performance. It does get a bit ‘techy’ though.
Sometimes there are many activities going on in the background that are unnecessary but do their bit to pinch resources from the thing you are trying to do.
I assume that, as it is a Dell, it is running Windows (10?). If you press “Win + I” then, click on “System”, then click “About” on the left-hand side and you should get a display of the tech details of the computer.
If you could copy the details and post them on here, it would give some idea of what the current situation is and how it might be improved, if at all.
Storage is very cheap these days. Even if there is no more room for internal disks, external USB disks are reasonably cheap and certainly usable.
Anyway, let’s see what it is currently then I’ll try not to make silly suggestions :-).