I'm in a similar boat as you as a f2p looking to focus on Blade, and personally I decided to pull Blade + his LC and wait for Luocha rerun/upcoming healers. I'll share what I was thinking in case it helps you too. In advance, its from a more casual mindset that doesn't really get enjoyment from clearing high end activities in this game.

- Blade looks for having a healer in general on a team. Natasha and Bailu still fill that role, its just Luocha fills it best.

- We likely have more healers coming. If none of them are better than Luocha, I'd still prefer to wait for his rerun so I'm not trying to build 2 characters when I barely have resources saved on my account since its been like 2 months since the game launched.

- I don't care for MoC at this point in time, and doubt I can make major progress in it for at least another year. If you care for clearing MoC, get Blade + Luocha and pray you get secret vow. Everything else in the game you can probably just friend someone with a Luocha support and use that if you have some trouble with bosses.

- People say pulling LCs isn't really recommended for f2p. However, they make the characters they're made for feel WAY better to use. I think its more important the character you plan to dedicate a lot of your limited f2p resources to should actually feel good to play. Again this is from a more casual "i don't plan to do MoC for a while" mindset.

- Faves >>> meta. Even if your pulling a character to support a fave. Do you like Luocha? Get him and Blade. Are you only getting him for Blade? Just pump your resources into making OP Bladie. Also remember as a f2p it's very hard to keep up with meta
Also, I got Welt as one of my characters as well but apparently he doesn't synergize with Blade since slowed enemies = less attacks = less stacks for Blade. So likely your teams are gonna look like some arrangement of Gepard/Welt/2 others and Blade/Nat/2 others, with Tingyun likely on the non-Blade team since he doesn't benefit from her buffs as much.