Escaping the Micros

It's going to be very, very difficult to have a positive winrate from the big blind. The small blind is actually a very profitable spot for me, but this can be put down to playing in games with many limpers. Definitely isolate a wide range from the blinds and have a secondary range to complete from the small blind and play aggressively on a lot of flops. We also have to realise that much of our losses from the blinds comes from folding preflop and choosing not to play out of position. This is going to be, in most cases, +EV overall. Playing a wider range from the blinds is another way to improve your winrate in those areas, but you're going to need to have a very solid postflop plan/reads on villain(s) when you choose to take a marginal hand OOP.

Playing profitable out of the blinds is a target rather than a goal to attain for me. Like you said, it's gonna be very difficult / impossible for me to play winningly out of the blinds in a 6max game, but reducing losses there could have a very big impact on my overall winrate I think.

Good attitude to have. I would say for now focus on isolating wider, esp from the SB, and looking at opening up your calling range a little vs the right people. How do you know if they're the right people? Look for leaks in their game. Do they always fold to 2 barrels when they check back the flop? Do they cbet too much? Do they have bet sizing tells? This kind of information can offset the positional disadvantage.

Oh, and please, please, please raise the BB with 100% of hands when the SB limps unless you have a reason not to (i.e. they limp/reraise a ton (add limp stats to your popup), they're a regular and limping is highly unusual (you can still raise here as it's sometimes a missclick, but proceed with caution)).