Help with picking free SR servant

These are what I have. EMIYA, Marie, Heracles, and Martha are at NP3. Nero is at NP2.

I’m thinking either Lancelot Saber because he sounds better than the sabers I already have or maybe Nitocris for farming. Idk if I really need her, though. I feel like I’m lacking in the DPS Caster department, so I think Nursery Rhyme doesn’t sound too bad, but idk. I also vaguely want to get Salter to NP2 because I love Artoria and salter.

I don’t think I’ll roll for anything in the recent summoning banner because I already have Merlin.

I’m a filthy casual, so any help will be appreciated!

EDIT: somehow sent it too early??? Please wait a moment.

EDIT 2: Ok, I’m done. read this

Honestly I feel that your biggest problem is you have a lot of the servants, just not leveled. (Note I know I shouldn’t feel like this but that many servants unlevelled frustrates the hell out of me and I’m pretty sure you’ve been playing for at least 2years). You already have the 3 best sabers to pair with Merlin from the 4* ticket. Just np2 salter. Lancelot isn’t going to change or improve your roster much.

RE: DPS Caster. Just a note Helena outdamages NR quite handily on np and on card damage. NR needs to be fed crit stars to get full value out of her

RE: Nito yes if you plan to farm and level the servants. But don’t rely on her for damage output in anything serious.