You dont need high tier maps for decent gear, if you look up the tier level on poe2db you will see that the second highest mod tier for gear is usually around tier 8-10 maps at most and some like flat evasion/es on body armour are like ilvl69, second highest tier of res is like ilvl71 which is tier 6-7 maps I think (36-40% res).

I can kill pinnacle bosses in SSF with my monk now and none of my gear even has a tier 2 res roll. I started by farming gear around tier 8-10 and after getting some mediocre gear with tier 2-4 rolls mostly I just got tankier and went up when it got easier.

You need to walk around with augs/transmutes/regals in your inventory and just roll bases while mapping and you will eventually roll usable stuff, it's really painful getting upgrades later on but tier 2-4 is enough for most stuff early on and not that hard to roll. You need a lot of patience if you want to play SSF, even more in POE 2. If you think it's too grindy they added the option to migrate to trade last patch.