Can I run more than one strategy at the same time?

Yes, you can run multiple strategies. They share one account, which is exactly the concern you're raising. Total exposure is the sum, not the max. Set your limits at the account level (max positions, max exposure, daily loss) rather than assuming per-strategy caps will keep you where you intend. If two strategies can signal on the same symbol, decide in advance whether you want that doubled or blocked; both are reasonable, but the default should be a choice you made.

This is the same point from my sizing post. Account-level limits, always.

Ran three strategies once back in the day, all long biased, all in tech. Thought I was diversified. Found out the hard way they were the same trade wearing different hats. Check the correlation of what your strategies actually buy, not just the rules.

Ok so if they share the account, what happens if two strategies want to buy the same ticker at the same time? Does it double up the position or does the second one just get skipped? Still fuzzy on this part.

It skips. Duplicate entry is judged against what the account actually holds plus anything still working as an order, so the second strategy sees the position or the pending order and does not send. You do not get two positions in the same name from two strategies.

Practical habit that helped me: keep a note of which strategy is responsible for each open position, and review them separately at the end of the week. Shared account for risk, separate books in your head for evaluation. Otherwise when the account is down you have no idea which one is actually the problem.