This 'point' is ludicrous. As ever with politics (evidenced in many Gen Elections) viewers and listeners take in JUST WHAT THEY WANT TO, as per any bias they have.
YOU (OP) only think 'Reform' is being given undue prominence because it's a special bee in your bonnet, if the LibDems were having constant press conferences, they'd get more of a mention. The other day the Greens elected a new Leader, he got masses of airtime, including a nice slot on Newsnight (when they haven't been heard of for months).
As has been pointed out, Reform have gone far ahead in the polls, so all the TV companies think they ARE news, and there's an argument that Farage (like him or loathe him -- and the latter is the only sane view) should actually be put far MORE under the spotlight, to expose his hypocrisy and fag-packet (lack of) policies.
For Maizie D, yet again with that "ignoring balance" comment you are completely ill-informed. I have no liking for any party, seen too much incompetence over many years from all of them), but I take in a fair range of TV and radio coverage, and the BBC does its best to be balanced across the political spectrum. They get more coverage of late on ALL channels, due to that recent surge in support -- greatly helped by all other parties looking even more inept than usual?!
Labour lovers will doubtless be screaming that the Rayner/flat coverage was massively unfair to the poor woman, Labour haters and the cynical neutrals will likely be wondering why Starmer took longer than 30 seconds to boot her out (imagine the noises he'd have been making if that was BoJo in Hove?!). For those with a long Labour memory, perhaps she asked Mandelson and Blair's advice re dodgy property deals (PM was suspended for corruption, what, 3 or 4 times? . . . .and is now Ambassador to USA).