I had a similar issue recently with harbor freight and northern tool. I couldn’t find any information on when the trailers at harbor freight would be sold again. I ended up finding a custom built trailer that a welder was trying to sell because he lost the buyer. I ended paying about the same as a northern tool trailer. I found it on my local craigslist/offerup.
Originally I was planning on buying a used utility trailer and fixing it up myself. However even the “low priced” ones were much more than I wanted to pay for a heavily used trailer. If I were to look again I would probably look around boat yards for an older boat trailer. It seems like a few people have had success converting those to a suitable trailer and I feel like I see more abandoned boat trailers than any other type. Good luck.