My Stupid Habit (Please help)

Quite a tricky criteria, but maybe Caster Gil once he comes around in Babylonia, he's also a 4* so you don't need to be super lucky to get him, plus he's pretty good but not as broken as let's say, Waver or Merlin.

Hans is pretty good too as a low rarity servant. Caster Cu I'd say is pretty alright as well, he is pretty much more niche but he's a good survivalist Caster. He's an Archer but he plays like a Caster imho but there's Nikola Tesla. And of course finally there's the mage Archer himself Emiya, who becomes pretty awesome once he gets both his strengthening quests, and his 1st one is coming this week. Not to mention he is somewhat lore accurate in that he's a magic-user trying to be an Archer, so his gameplay is both flexible and unique.

Overall my biggest recommendation would be Emiya (Archer) for current one that's available, and then maybe Gil (Caster) once he's out.

Hmmm... well I did have fun using Dantes during his event. Outside his tier list, he is good. He's an Avenger, is edgy, has cool attack animations, what more could you ask of him except for buff interludes? Kidding on the last part but he definitely needs a buff.

Gilgamesh is a good candidate. Setting aside his 5* rarity AND horrible personality in the franchise, nothing is better than snapping your fingers and firing weapons like bullets out of portals from the dimension of your own personal stash, while watching your enemies get shredded to nothingness (literally).
And an Anti-World NP.
And a Divinity status.
And wearing golden armor over a six-pack.

Robin Hood is the perfect candidate here. He's an archer but has more assassin like(sabotage skill) methods. In Fate/Extra, his thing is poisoning and he prefers to avoid frontal confrontation and prefers guerilla warfare. Not to mention, he's one of the best single target archers in the game. Then Fuuma Kotaro is another option as well, he's a ninja(who also has the sabotage skill). That's as tricky as you can get