3 Mobile 5G Broadband - they want to give me an external antenna (tech installation).

I'm looking at getting mobile broadband, and decided to try Three's 5G product: https://www.three.ie/broadband/broadband-deals.html
It looked like something that could be self-installed but when I do the coverage check using my Eircode, it only offers "tech installation":

"This plan has tech installation
One of our experts will handle the installation of a 5G receiver outside your property and a Wi-Fi router inside, ensuring you benefit from the highest available speeds in your area. We'll contact you within 2 business days of your purchase to set up a convenient appointment."

The next page says they'll install a "5G CPE New Radio Outdoor router product" and a "indoor DX3301 unit". So they're not offering me the "plug and play" gadget (ZTE MC801A) that appears in their TV adverts and on their website.

For what it's worth, we're located in north County Dublin. The nearest Three mast is 450 m away. I'd have thought that was close enough for the ZTE unit to work well?

Has anyone got this setup internal/external setup from Three, and how do you find it? I assume it means running a cable through the external wall, somehow? (I'm not keen on that; our home is a timber structure, recently retrofitted with insulation, vapour barrier, breathable membrane, etc, to achieve the air-tightness level needed for an A1 BER. Drilling holes in the external wall is the last thing I want!)

For what it's worth, Eir's website seems to be happy to sell me their self-installation gadget - a Huawei 5G CPE Pro 5. Vodafone's website will sell me a 1GB fibre connection, which is odd as I'm pretty sure there's no fibre near our house…