The Spitz and the Beryl run on the same software, by the same company. But the Spitz has several variants which range widly in price due to the price of the cellular modem.
The 5G wifi 6 version is $399.
The 4G wifi 6 version is $329.
The 4G Wifi 5 version is $129.
The Spitz also uses a standard barrel connector DC5521 and is compatible with 12v systems up to 24v. So you can buy a DC5521 pigtail and wire it to a switch on your RV switch panel if you want for a clean install. You can run it on house batteries for a long time. Also comes with a wall mount.
The Beryl uses a USB-C 3amp connector. USB C is very standard but 3A might be a little challenging to find. But there are plenty of 12v to USB-C adapters on amazon. Also ones that plug into the cigarette port.
I owned the TL-WR902AC, it was my first travel router like 10 years ago. It didn't work well at some hotels and I couldn't log in properly. I ditched it as soon as the Beryl came out. GLI.Net's software is significantly better, it's travel router perfected and based on OpenWRT. It works much better than TPlink's software which is adapted from their home routers and not as capable with edge cases with hotels.
If price is a factor, GLInet has the Opal router which is Wifi 5 with a less powerful processor, but uses the same software as all their other routers. Having a less powerful processor means it'll be slower when using the built in VPN features. But for $30, what do you expect. As a simple travel router, it works great if you use the VPN software on your computer or tablet instead.