Somedays are worse...

Communication is indeed key in these situations.

The thing is, communication is not always positive.
That doesn't mean it's not valid.

Brother m76 's missus seems to be communicating her position very clearly and consistently.

The thing is, what she is communicating with her actions is not what Brother m76 wants it to be.

It almost seems that a woman that has decided on celibacy as the watchword in a relationship also revises how she categorizes her spouse from lover and sexual partner to a much lower status of "best friend" I think this is because she wants to hold tightly to the male who is likely the breadwinner and her financial sponser in life. I'll bet good money that when there is "date night", putt putt, dinner out or whatever the activity might be it is the male spouse that is paying the tab. The shared activity no longer has much of an intimacy component to be found, but is pretty much just two friends sharing an activity they both enjoy. It has no foreplay component to it for the refusing spouse.
I often see on dating sites a woman states she is looking for a best friend. That has become a "red flag" of sorts. Few males are looking for a woman to be their best friend, because most men don't think of best friends in a sexual role. I suspect most women don't see their best friend in that role either.

Once you are placed in the friend zone it is difficult to get out. I don't recall a single posting here where someone in a SM has said that being a spouses "best friend" has reslted in increased intimacy, or any intimacy at all. greatcoastal has posted a number of times about being friend zoned by his dancing partners. 
With few exceptions it has taken a dramatic announcement by the refused that a seperation or divorce is coming if things don't change. Announcing that a FWB will soon take the place of the refusing spouse sometimes works, but often the reset is short lived,
a few months being the norn, mirrororchid being the exception. 
Reading here seems to reveal that having "a talk" in which the sexless partner announces they intend to go outside the marriage  has worked for a number of the women here. Men seem more inclined to allow this where women seem more likely to oppose it. My X preferred a divorce.
So the decision facing you now seems to be do you stay celibate in the marriage or do you look for something somewhere else ?

If you haven't already you need to talk about your feelings on the lack of sex. She may not realize how important the sex is to you. I recently had this conversation with my wife. I'm hoping that now that she knows how important it is, she may make efforts to change her stance on sex. If months go by and there's still no effort on her part to "compromise" as she puts it, I know that from here on out if I stay, it'll be as friends, nothing more.

Sorry man. I get that, you likely feel trapped. The only advise I can give is make sure you make time and do things for yourself. I'm a volunteer, I visit my family , I do sports in the evenings and meet some guys on the weekend for games, all this on my own. We still do things together, but I make sure I have stuff that's just for me.

h "I have nothing for myself anymore. Any extra time I have usually goes to extra hours at work, house chores, and posting in online forums like this one. I haven't seen any of my friends socially since before COVID and considering they haven't reached out to me even one time, I don't think I'll see them again."

Have you reached out to them? Friendship goes both ways. Also, many people stopped socializing due to Covid and may still be getting back into the swing of things.

The time you are spending on on-line forums could be devoted instead to outside activities that allow you to make friends and reconnect with old friends. You don't have to live such a lonely and miserable life.