Just get the 93. I put my 73 on my unit because I already had it and it lasted me about 2 weeks before I bought the 93. If you can still find a 93 with the GT54, they're about the same price as the 73 with the GT56.

https://www.amazon.com/Garmin-Keyed-Assist-Touchscreen-Chartplotter-GT54UHD-TM/dp/B07YYXDNK9