Players in my group are super inconsistent. What would be a strong character that can help cover what we may be lacking on a given night?

Currently our group consists of:

2 Wizards (I think) 1 Cleric (she said she didn't want to heal, but would if necessary) 1 Monk 1 Fighter of some sort and me, an Artillerist Artificer.

Truth be told, I'm not sure I've enjoyed the Artillerist as much as I'd thought. I'd previously played a Fighter, and while they're super plain-jane, I actually kind of enjoyed the simplicity of not having to think too much about my turn in advance, I could just go with the flow.

The DM and I already spoke about me not really feeling the current character, and that I could change. I've thought about switching to back to the Fighter (since he was actually in the same world in this campaign, and roughly our same level anyways).

HOWEVER

I've noticed that unfortunately, everyone has been super flaky with this campaign. The worst part is that people are no-shows instead of just saying they can't make it, which I think is sort of shitty personally, but whatever. Thing is, it's made for some REALLY difficult fights, and it's all the worse because the DM even kind of commented once that he's trying to figure out how to balance fights because some nights, we don't have a healer, or a tank.

The Monk is the only other player (besides the DM) who has made every session, and one of the Wizards has made most of them. However, that Wizard doesn't have any sort of healing abilities.

Most frustrating for me personally, my character has reached 0 hp in....actually now I think about it, I think it's been literally every single fight we've been in. It could be that I'm just not being clever enough with my character (we're only level 3), but I'm just not feeling it.

So, what are some ideas?

Part of me thought about bringing back my old character, who was a Fighter, and maybe just going the Champion subclass with him, since it seems super straight-forward. He's already a half-orc, so it seems a decent enough basis for a character. He was level 4, but had never declared a subclass, and since our party is literally headed to the place he was last at when my last group fell apart, it would be super simple (both the DM and one other player know the character, so that could be kind of fun).

But then, maybe there's another class that would be able to cover more of our bases as a group? Because yeah, it definitely sucks to feel like we're walking into a boss fight that is balanced for entire roles that aren't present in our party.

I don't really like the idea of player a healer, but I'm worried we're going to really be stuck on sessions where we don't really have a good composition for the party.