Solid openings requiring less theory for low ranked?

@Mickackou You should firstly develop your tactical vision and understand what positional advantages are often even more important then material. For that the best lines are sharp openings, all kinds of gambits etc. where both kings are in danger (King's Gambit for example). You should not worry about the fact you don't know the theory: your opponent won't know either. You should spend at least 30-60 minutes to see some possible lines and common traps in some book (Fundamental Chess Openings as an example), but there is no need to learn the theory throughly. If you were destroyed in the opening, just look after the game where you went wrong using engine and lichess Master's opening book.

More positional openings make little sense if you are likely to just blunder a piece suddenly, ruining all the slow progress you've done.

I'd advise the English Opening. It is based on ideas more than memorized lines. Of course, openings are not the most important part of chess, but this answers your question. I am working on a study of the English opening right now (currently uncompleted) that you all can check out.

1. c4

#6 I think I taught that lesson that day. ;)

Try the caro-french

@howchessYT
french definitely

I don't think it's a good idea to play systems.
I remember hearing somewhere from a chess coach that he told his students not to play "universal" systems because they often end up playing moves without understanding much about the opening.

French definitely not: not solid and requires lots of theory.
Caro-Kann is more solid and requires not that much theory.
1 e4 c6 2 d4 d5 3 Nc3/Nd2 dxe4 4 Nxe4 Bf5 is solid and has similarity with the London system you play as white.

Caro-french not caro-kahn and french

Do you mean 1 e4 c6 2 d4 e6? I do not know if that qualifies as solid.

Not that solid but very useful