Depending on your class and spec, you may be better at soloing, but at least up to Tomb of Sargeras I’d argue that there’s not much you can’t solo in Legion raids. And yes, even with the Shadowlands class changes and level squish, most of these raids are still fairly easily soloable, with some notable exceptions.
Yes, you can now solo Legion raids, and Blizzard has even updated the Legacy Loot system so that Legion raids use it.