Reddit mentions of TP-Link Omada AC1200 Gigabit Wireless Access Point | MU-MIMO Outdoor WiFi Extender | Seamless Roaming & Beamforming | PoE Powered w/ PoE Injector included | Cloud Access w/ Free app (EAP225-Outdoor)

TP-Link has this one

There are more high end ones, and you can get outdoor enclosures for them. But that appears to be the cheapest one I've found that's meant for outdoor use.

1. Unlike the other poster I think you should get rid of your cable modem/router combo. They charge you anywhere from $8-$15/month rental fee. Go on amazon and buy a surfboard modem. It’ll pay for itself. For the router, if you’re not big into settings, you might try to google WiFi 4-pack for $300 at Costco. It’s a set it and forget it solution.
   
   
2. Metal & WiFi don’t go together. You’ll need an indoor and outdoor solution. You could get a two antenna AP like this and an antenna extension cable to just get one of the antennas outside. Or a google puck inside placed on the window to broadcast outside.
   
   
3. Buy cat6 outdoor. When you buy the terminals, get either pass through or with the little holder. Making it would either of those methods is a nightmare.
   
   
4. strategize your puck placements. If by wire put them where people will use devices. Like next to the TV. If by WiFi meshing place the puck half way between you and the point. If you get poor signal somewhere putting a puck there will get poor signal too.

If everything MUST be self-contained and indoors (read: no drilling or slightly open windows)
Consider something like an AC68U (TM-ac1900 refurbished/rebranded for as low as $50ish on amazon/ebay), set it in media bridge mode using the 2.4GHz band to connect to the local internet and the 5GHz to connect to the site.

This SHOULD give a much stronger connection than going with a traditional extender.

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As far as "outdoor wifi antennas" that would probably be something akin to an outdoor wireless access point.

https://www.amazon.com/TP-Link-Wireless-MU-MIMO-Gigabit-EAP225-Outdoor/dp/B07953S2FD

https://www.amazon.com/gp/product/B01N9FIELY/

https://www.amazon.com/gp/product/B01N1VMBUR/

You MIGHT actually be able to do something somewhat similar to the above with just an AP. I would need to research it. Likely something to do with "mesh mode" (mesh is a loaded term which means different things for different products FYI). Also be aware that there are different levels of "weatherproof" and "outdoor". Some devices assume that they're under an awning.

If you have the opportunity to go wired, use it. WiFi extenders usually decrease performance for everybody because air is a shared medium.

Imagine a guy screaming in your direction. If you shut up and listen, you can repeat what he said in the direction of another guy. The other guy will have to wait for you to stop yelling, then answer, you'll have to wait and yell at the first guy.

Sounds pretty inefficient? That's a WiFi extender for you.

Use MoCa to get signal to your bedroom. Put a switch there if you want to use more than one device. Put an AP there if you want wireless.

MoCa adapter $169.00

Dumb switch $15.99

Access point $75.88

So, you'll have to shell out $260.87 for a setup that'll be orders of magnitude better than your WiFi extender stuff.