You can try Affinity Photo, it is fairly affordable and works with HDR types of images. There are plenty of tutorials available for doing just that as well as Affinity’s online help section.
p.s. You may want to change your title a bit. The very recent MacOS 10.15.4 Catalina update turned on support for HDR monitors, so if you have one connected to your Mac, you already have ‘HDR support’ in a sense.