I’ve always played as a single player since 2016. I’ve only fleeted up during faction warfare roams, but that’s about it.
Also, the isk can be better in low sec for the independent solo player. Plus logistics is easier. Find yourself a few 0.1 and 0.2 systems and belt rat. Clone soldiers will spawn that drop security tags worth 30m each, and you’ll also encounter the occasional faction spawn as well (Mordu Legion spawns can drop BPCs worth up to 700m, IIRC). You can rat in a cheap Algos for less than 15m, and bring out a cheap Gnosis when encountering a Mordu battleship.
edit: Gas mining in low sec is also good isk. A solo Prospect can huff Cytoserocin and earn up to 100m/hr.