Not sure which map version you mean by "20.23.25" as Garmin's naming convention is, for example, "City Navigator North America NT Version 2025.10". I'm not aware of a problem with street name rendering being problematic on SPs unless in all capitals in CN maps .... but imo that's just another reason for using OSM on these devices now. I have a 2720 with an LM subscription but because of the hoops Garmin makes us jump thru i don't even bother trying to *update it with CN maps anymore. OSM is easier and they are just as accurate for day-to-day road use afaik. SP devices can't use all the Garmin distracting eye-candy extras such as JCV anyway, the lack of that isn't a negative on a MC anyway imho.

*GarminExpress connects to devices in Mass Storage Mode (MSM) only, same as how Windows File Explorer sees them. SP 2xx0 and related devices connect to a computer in Garmin Mode which is why they aren't seen by GE or Explorer. Garmin Mode is similar to the preboot mode in modern devices, those modes only show limited information under Device Manager (as "GARMIN Devices"), so can't be 'browsed'. There are "ways" to get around all that but as i said it's not worth the trouble especially for everyday uses without deep technical knowledge of how to flash maps to non-MSM (aka region-only) devices. Such discussion here is barely allowed however, because it skirts the forum's rules on not posting anything contrary to Garmin EULAs.

If you're determined to use a CN i'll help you once you locate the GMAP folder (PC installation) for the required version, but i can only tell you how to do it but not actively supply files or use tools for converting to a usable IMG file for you.