Is this not just a clear case of denial?
Your guests are looking for well paid jobs in their chosen fields, because that's what they used to have, so they should get the equivalent here. Except... they're not comparing like with like.
Say I moved to France - I'd expect a job that allows me to have a similar lifestyle to one I have here. I've worked hard my whole life and I speak the language of the country. I wouldn't want a low paid job. I'd be comparing things to life in the UK. But the difference is, I would be an economic migrant. I wouldn't be fleeing death and destruction. If I was, I'd be grateful for anything to survive.
That lifestyle that your guests used to have just doesn't exist anymore, because their country is at war. It's not a pleasant thought to have, and it forces you to think that you might never go home. That this isn't a temporary jaunt abroad. This might end up being your new home.
What they need to think about is what kind of job they could hope to get back home right now and use that to manage their expectations of what jobs they can get here that are better. They're comparing their old lives with their new lives and unsurprisingly, their new lives are falling short. But in reality, they should be comparing their new lives with the ones that they got to run away from.
I suspect there's also a lack of understanding around how their accommodation in the UK is being financed or that an end date was always expected.
Thing is, it wasn't a well thought out scheme. People took in Ukrainians because there weren't enough council homes to house them - there haven't been enough council homes for the existing population for years. A the end of the six months, what was going to be different, if the council hadn't spent that time building new properties?
So, I'm going to add in a case of denial from our Government, not just the guests.
Some of the people who left Ukraine left largely unscathed, and need to adjust their expectations. Others witnessed things that are bound to have had a lasting effect, and is six months really enough time to process that trauma, integrate into a new country with a different lifestyle and somehow find paid employment and somewhere to live?
I mean, work and housing are both top causes of stress. Work, housing... and a war. And probably deaths of people you know... I'm not saying six months wasn't a reasonable time for an average person in the street to offer to host, but I am saying it was wildly optimistic for the UK Government to expect everything would be magically resolved at the end of that period.
It's a tricky situation for the OP, and I do sympathise, because the offer to host was made with compassion and kindness. I don't have a spare room myself, but if I did, I don't think could have been as generous. Our Government has put you in this position, and I hope you can find a way to bring the situation to a satisfactory ending for all parties.