Given a Zone 5 rating here:

https://conifersociety.org/conifers/metasequoia-glyptostroboides-ogon/

What a great view, Grant.

I don’t have Ogon, just the species, but it is fully hardy for me so far. Mine’s been in the ground about 5 years and has grown by leaps and bounds.

IMO you're close to its cold limit but should be OK.

The other garden discussion site (that begins with a man's name) reports these growing successfully from Alaska to Texas and everywhere in between with the exception of Montana, Wyoming and parts of the arid southwest. Numerous reports of it doing well in Iowa, Illinois, Michigan, Ohio and other cold winter climates.

I looked, the site assigns it USDA 5a. Not seeing the reference to Alaska, there is one post from 2006 saying a friend has it in full exposure in USDA 4a Minnesota - without the critical detail of how long it has been surviving that situation.

It is listed as reported growing in at least 5 locations in AK, all of which are listed as a USDA zone 3b. But no, there is nor indication how long they had been growing in those locations.

I know of 2 up here by Minneapolis 4b in very sheltered locations. Mine gave up the ghost a few years ago after several years in the ground in a fairly exposed location. Species is hanging in there.

Aside from the cold issues in marginal areas, aren't the various cultivars of this species less robust than the species (slower in growth, more inclined to issues)?

The ones selected for slower growth, yes, grow more slowly. The ones with golden needles are generally less robust - same as with all plants - due to less chlorophyll production. I haven't experienced any issues with any Metasequoia though.

I had the Ogon, and for some reason, foliage started turning into a creamy, white color, then there was a premature April heat wave with dry winds and the young leaves looked like someone took a blow torch to it. Absolutely no issues with the all green species, but I would like to try one of the numerous cultivars again.

I find that it is sometimes difficult to site the yellow cultivars. Too much sun = burn. Too little sun = green. Can take some time to get it right.

Mine went in last Fall, and went brown along the leaf edges in second half of growing season. The tree managed to survive meekly through its first year though with no real growth. But except for Fruit trees nothing seems to grow here first season.

I had a couple of metasequoia in the Twin Cities (anywhere from 4a to 5a depending on who is doing the measuring). One died after a couple of years, and the other one is still hanging in there. They are prone to winter dieback, and while they can do really well in the summer, I wouldn't call them hardy.