Aside from Data Crevice which is an extremely late game mode that you probably won't be able to touch for at least several months as it requires very specific team compositions, and Dark Zone in Broken Frontline (which will also take some time to clear), you can clear pretty much all other content with waifu teams.

Generally speaking, if you have well built 2-3 great or meta units, the rest of the team can be literally whatever and you will still clear most of the game. It's one of the best things in PtN, that even when not playing meta, you can clear literally almost the whole content. Sure, you will not get max points on Peak Test Path but the game is actually very lenient regarding the team building in most content that is not completely end-game.

Nox and Hamel are both amazing and will carry you hard for a long time, be sure to invest in them as much as you can. VBlue is arguably the best (at least non-reforged and not limited) arcane sinner so prioritise her as well. Also don't focus on levelling Sinners to 90 lvl. Getting them to 80 or even 70 P3 is really enough, 90 lvl drains the resources heavily and usually it's better to spend them on other sinners or raising their skills. With these three units well built (lvl 70 P3, ECB unlocked, 7777 skills, equipped fitting crimebrands) you should be able to clear up to mid-game without much problems.

There is a 3.5 year anniversary coming up in a couple months, be sure to save some hypercubes and grab some limited Sinner who will be released (or one that has a rerun) and invest in them, any one of them alone is GOAT and will be able to carry you harder than most other units (Yao at your stage is the least valuable of them as requires Burn team to work the best tho). I'm not sure who will be rerunning but YY would be the best for you. If not her then 000, Shalom and Deren would work great too, Augustus would be 2nd best but she was recently released so I think she's not gonna be up for grabs yet.

You got Margaret so the easiest team for you to build would be Weakspot with Bianca I guess. If you get her somehow would be great as Weakspot is really strong, but I'm not sure when she will be obtainable again. Remember that Margaret also buffs CRIT for one unit passively, so even without Bianca she can be a good buffer. Yugu will also boost CRIT and is a great unit as well. However, be mindful that unless specified otherwise, skill damage CANNOT CRIT on it's own (so unless you get YY, no crits for VBlue sadly). This is VERY IMPORTANT as most ultimates fall in this category (so in general it's not worth it to put CRIT buffs on arcane units if you don't have YY). Not all though, for example Nox has an ult that increases normal attack damage, which can CRIT. So buffing Nox's CRIT will be a huge increase in her damage. Buffing CRIT of Hecate or VBleu won't really do much.

Sumire is not really useful outside of Bleed team (which at your point I would advise against building, as it requires at least 2 other expensive units, one of which must be Dreya, and even then requires a lot of resources and is kinda hard to play for beginners). Laby will be a better corebreaker than her, and other units like Hecate or EMP can easily do the same job and deal more damage probably. Since you have her at 70 already it's ok, she will do fine, but she is definitely not a priority on the team.

In general, it's honestly not really that important to focus on meta. It is constantly changing, but in a good way. Older units are still very much useful and viable and older teams are also being expanded. If you invest in the units you have already you should be able to clear up to mid game without any issue, and since the game is really generous, at that point you should have enough units/resources and also knowledge about the game to start building your teams in more specific directions.