If I loan money to my LLC multiple times, over time, for different reasons, is it okay to use one loan account in my chart of accounts? Or should I set up a unique loan account each time I loan money in?
You are not "loaning" money to your LLC, You are increasing equity and if you wish to repay yourself, which is never required, it is equity reduction.
You need a set of 3 equity accounts for each member of the LLC. Member Equity, Member Draw, Member Contribution. And make these three all sub accounts of a parent Overall Member Equity account for each member tgat you never post to but acts as a summing account.
So, personal money in is Member Contribution. Any and all money out to you is Member Draw. Profit or loss is passed through to your personal return and year end profit is posted to retained earnings, and then to equity on day 1 if not disbursed.