I have to say I am the opposite and always have been.
Sure, in my teen/young adult years I wanted friends and used to thrive on the energy in public. But I was never upset at being alone. Alone meant I could do what I wanted, how I wanted and when I wanted. You need people out of the house to do that.
So, when family was absent and I had the house to myself I was good. While I am comfortable interacting with people at work, I've always sought my own company.
But…I am an introvert, a loner. And a member of Gen-X, the latchkey generation. I'm used to being alone. And I married a woman who is the same. We're comfortable being in opposite rooms all day because we know where the other is and we can just go talk to them if we need/want to.
I managed to make work from home permanent after Covid and I'm the happiest I've been at work. Before I had to carve out my own space. Now, I'm home in my own space. My problem isn't loneliness, a lot of the time it's boredom (except when we're busy).
It did take me awhile to adjust to this new job (I will have been here five years in February). But that was primarily because at my last job the business was sold (small, family owned business) and the buyer had their own people. Most of use were let go. After 19 years doing what I do (at that time) I had to adjust to a new way of doing it with this new job and so anxiety was high. But not because of loneliness.
My wife and I have a year and a half to go and kid 1 graduates from college. Still some time to go with kid 2. But eventually my wife and I get our pre-kid lives back (and the currently occupied bedrooms!).
I can relate to this post completely, and, by temperament, am probably quite similar to you.
I love my own space, and my own company.
And I am also quite struck by what you write about choosing to be in separate rooms, yet in companionable and congenial accord; my parents were like that (to the stupefaction of several idiotic relatives on both sides of the family who could not conceive of a happily married (and mutually respectful and affectionate) couple in a relationship where each partner gave the other physical and psychological space - and respected the need of the other partner for this - without resenting it or demanding intimacy, attention or proximity as proof of affection), and I, and my brothers, are, as well.
To the OP,
@Bubble99:
You may be conflating and confusing two separate things, namely, boredom in a job and loneliness.
Boredom does not equate to loneliness, it means that you are insufficiently stimulated by, or interested in, your work; that is a professional matter.
Loneliness is something personal, and comes about from feeling a lack of human companionship, something that is often alleviated, or ameliorated, by the existence of friends and/or family with whom you enjoy close - or, at least, - comfortable ties.
Some people fulfil their needs for personal communication, encounters and engagement at work, but, ever since the pandemic, and the growth of working from home, people who are extroverted - who have a strong need for constant human companionship - may have found meeting these needs increasingly difficult.
However, those of us who are more introverted (among whom I count myself) thrill to, cheer to, the demise of (or decline in) having to travel to work and meet (and talk to - remember your Yeats:...."....I have passed with a nod of the head, and polite meaningless words, or lingered a while and said polite meaningless words.....") and work closely alongside (the open plan office is the spawn of Satan, to my mind) people each and every day.
My advice, for what it is worth, would be to find something that interests you, and to try to meet people through that (book clubs, music, sport, etc).
Professionally, perhaps you could make an appointment with your line manager, and ask for greater responsibilities, or further training, with a view to be offered work that is more challenging and rewarding; if that doesn't work, perhaps it may be time to start looking for fresh employment opportunities.
