The advice to get 100 dives before solo is pretty good.
You can accelerate this learning by paying for instruction, find a solo friendly instructor, pay them to learn.
You need a redundant gas supply.
I'd recommend starting with a 40cu ft stage, pay someone to train you on slinging and utilization.
imo solo divers need to have a spare mask, shears, redundant gas supply and do at least an hour of cardio a week.
Even still, if you dive alone you need to be ok with dying alone.
You need to have proper life insurance for those you'll leave behind.
I've been solo diving primarily for 30 years. Things are way less spicy nowadays, proper equipment and instruction help, experience also helps...but there have been some damn close calls along the way that shape my advice.
You can choose to take or leave it. Have fun, good luck.