Stay FBM or switch to FBA or just more ads?

So… it’s that same old tired question, but with so many changes it is hard to know anymore. I sell items for $5 and send by letter mail unless over $10, then use tracking. Needless to day, those that go out by letter mail, about 10% say they did not receive so I go ahead and do a refund. I’m sure a lot of it is fraud but I chalk it up to cost of business. But postage is going up, and I can’t really ask for more on these items. So the next thought is do FBA but sell in sets of 2 or 3. I do about $300-$500 in sales a day and the cost of the item is low. But it is the labor because I create all the items myself (I own the brand so own all the buy boxes). I feel like my growth has plateaued and so I’m considering FBA, but I am concerned about all the fees and quite frankly – since it takes a bigger cut it means more work for less money since I create the items. So do I just up the bids on my ads or bite the bullet and go FBA?