If you use Lightroom like I do, all you need to do is snap a photo with your cell phone to record the GPS, then at home in LR, import all your photos including the cell phone photos and sort them by time taken. Then, select the cell phone photo click the map module and it will show the location. Then just drag any other images taken around that time from your filmstrip to that location and they are all geo tagged. I tried an accessory GPS unit and it broke the first time out. This is much simpler. The file structure I use (which Lightroom follows on import, is:
Year, YearMo, YearMoDay ...like this.
2021
202101
20210101 (with all the images, sorted by date taken)
I'm usually the only one using the camera so my wife always takes a phone shot, doesn't matter of what ...even a pile of sand, since all we 'need' from that one is the time taken and the GPS coordinate.
We've travelled all over and using the Map module is great because you can also get information about the area, like landmarks etc. and add that to your keywording.
Most of the bluetooth models I found via Google seem to have gone out of business.
An excellent example of why asking for specific product recommendations is deemed not very useful on Photo.SE: after a while the answers are outdated and not useful. Voted to close. Perhaps previous questions on geotagging have more general solutions for your problem? \$\endgroup\$