If the money to buy dual sided pedal based PM's is very trivial to your finances, then why not? But single sided will give you much more than you have now. And for much less if you go with a very good crank based brand as opposed to a less expensive but not quite so good pedal based brand. And as for whether your power is balanced left and right, it's not that big a deal. Any effort you take to strengthen the weaker leg is really just ignoring the other leg and not increasing it's potential at the same time.
What is your current crankset? If it's most any of the 2 piece Shimano cranksets, then you can just get a left side crankarm with a PM. 4iiii has some pretty decent prices for a left side crankarm. And all you really have to do is match the crankarm length. Doesn't matter if your crankset is a Tiagra or some other Shimano 2 piece hollowtech II crank. DuraAce, Ultegra, 105, or Tiagra crankarms all fit on the left side of that crankset.
I doubt any will notice that you have a different crank on the other side that they can't see at the same time. You might not be getting your true power, but it'll be close enough. And again, much better than none.
If you do go with a 1 sided crank based PM, then the 4iiii and I assume others are able to work together to give you 2 sided PM info if you ever decide later to get a right side PM.
However if you are competing regularly at a amatuer or higher level, then my advice will change and tell you to get the dual sided pedal or dual sided crank PM. But still, only if it's effect on your wallet is of little notice.
Last edited by Iride01; 12-10-23 at 01:29 PM.