If it isn’t putting on any growth, I think that is the problem. I had trees I planted at 1 rental and they never grew much (4 growing to 4.5’ in 4 years). The soil there is a bit dry, with grass browning during the summer. I added fertilizer and top-dressed with mulch (year 4) and it still didn’t do too much. The only tree producing a few fruit was the one I planted a year later and worked a couple buckets of composted leaves into the soil (increasing water-holding capacity).
Now, contrast that with a rental which always seems to have plenty of water (runs off the end of a long street and it wouldn’t surprise me if there was some other source), At that one, trees were up to 10-12 feet at the end of year #2 and had big crops in year #3.
This year, I’ve been watering (heavily and at least weekly) the trees at the dry location. They are putting on growth and several of them have quite a few fruit as well. I’m sure the 3+ weeks of hot sunny weather has helped as well. But, if I wasn’t watering, I think only a few sites would have had enough moisture in the soil to properly take advantage of it.
So, if your tree isn’t growing, it probably won’t be producing either. Growth doesn’t guarantee production, but if it isn’t growing that is probably the first thing to fix. If you have good growth 3-4’+ per year and still no production, then it is time to check to see if it is getting enough sun, certain nutrients (Borax?) and pollination. I’m also exploring cutting back the vertical growth to re-direct it into the fruit. But to be able to have any impact, there has to be some growth to re-direct…
So, my suggestion would be to add organic matter when planting, fertilize and water the trees heavily (but not daily- maybe weekly).
Seedlings take forever for me. Even when I put it in ground and baby it. The biggest are maybe 4’ after 4-5 years.