Unfortunately there is no easy way to determine this. You'd need to find out what frequencies and tech work in the areas you'd be visiting. For example, some countries don't support certain radio frequencies as they're used for something else.

The easiest way I find is to use a country or region forum and just start asking questions. You are very unlikely to be the first in the destination to do this. Most hotspots are relatively simple to configure and if using a physical sim, most of the work should have been done for you.

I think travel router is mostly a thing of the past. I still have one from the old days when many hotels only have ethernet for internet. And there were some hotels that only allows 1 device to connect to it per room. If the place already have WiFi now, a travel router is not going to really offer anything extra other than maybe a built in VPN.

If the room has an Ethernet connection, I setup my own router.

I agree with Garza. I prefer my own router where possible...

1) VPN.
2) the hotel has no idea how many connections/devices you have. Makes it harder to track.
3) in-network sharing is easier.
4) ease of connection... No need to register a new SSID (less need to manage your network settings)
5) Iot devices... Many people carry devices that aren't easy to connect to random WiFi networks... WiFi cams for example (your own mobile security system)
6) not common now, but some places do still charge/limit you for number of connections.
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It might be a bit more bulk, but depending on your travels and security requirements, there is still a market for travel routers (or even using a regular router).

How about 'easy to configure' travel routers? I'd mostly use one to capture wifi and broadcast to several phones and ipads.

There's a difference between a travel router and a mobile hotspot. Mobile hotspots (from the service provider) in general are pre-configured and locked down. You can use them while you're out and about. Travel routers don't provide any phone service and depend on you to do the configuration (usually not very difficult), just tedious).

The way I see it, a travel router just means it’s a portable router (whether the WAN is via ethernet cable, WiFi, 3G / LTE), which creates it’s local network and output that to cable or Wi-Fi.

A hotspot device (aka Mi-Fi) is a type of travel router where the WAN is via its built-in 3G / LTE modem, and creates its local network tied to its Wi-Fi access point.

I used to have an old Huawei, 3-branded Mi-Fi 8 years ago, did the job just fine, though battery was an issue. Could be used with any provider, just check in the SIM card, and configure the 2G/3G WAN & Wi-Fi LAN as needed.

A non-hotspot travel router can be as plug-&-play as any operator’s hotspot - I used to have one of the Netgears, fairly straightforward.

I used to carry a regular router on business trips. But sometime during the pandemic (maybe before then, hadn't used it in a long time) the router died. For the most part, I generally don't need mobility while on the road (just where I'm staying and onsite) but I've been told by some out of country colleagues that they've been hitting more dead zones as of late. I guess with WFH and remote learning connections are getting stressed. Planning to pick up a MiFi device before my next trip just in case.

I naively hopped onto this thread (and the other one on the smallest travel router) thinking technology would’ve moved on substantially in the few years that I haven’t been travelling.

I assumed a relatively inexpensive combination of router/extender/mifi device incorporating a 5G modem would exist. But the 5G mifi-type devices seem few and far between, very expensive, not great reviews and still seem to rely on physical rather than eSIMs. The only real 5G option seems to be hotspotting a 5Gphone. Is anyone doing this regularly? I’d have a slight worry it will kill the battery life and overheat the phone if regularly used.

Time to dust off my 5 year old unlocked LTE mifi and I’ve invested in a GL.inet Mango as an interim travel router.

I think that's mostly because 5G is still relatively new. Not a lot of places have built up the infrastructure to support it properly. Many of the 5G networks I've read about aren't even using 50% of their supposed capabilities yet. Give it a bit more time.