Farscape was barely sci-fi. It verged hard into science fantasy, where the science part was essentially magic in space.

Doctor Who is pure science fantasy. But it's science fantasy more akin to star wars (which is part space opera, part science fantasy) where there's a certain degree of internal continuity, even when canon is thrown out the window or just retconned. For Dr who, the consistency is in the fact of time travel, and the doctor being a much more potent creature than they seem on the surface.

The absurdity of the doctor is that it's an excuse to run around, utter technobabble, and tell some surprisingly interesting stories that would otherwise be unrelated. That patchwork is likely why you can't/won't accept the absurdity of it the way you can with farscape where it's more ensemble character driven.

Doctor who relies on the doctor/companion characters being your "in" to the story. The farscape characters are the story itself. It's closer to more firmly sci-fi sci-fi like Babylon 5, or the second Battlestar Galactica in that regard. But it also does the situational drama the way star trek did it, to some degree. That is what gives farscape its charm; it pays homage to science fiction tropes, with puppets lol.

Now, modern Who does a bit more character work here and there. There's a little less of the one-off episodes, sprinkled with the usual recurring villains, and the long term story arcs are centered more on each companion/doctor grouping than the older Who.

Sometimes, even as a Who fan from the eighties, watching Tom Baker grin and give his wink-and-a-nudge joy to the silliness of it all, the absurdity can be hard to accept. Not impossible! I do accept it, but there are times where I have to choose to do so lol. But Pertwee was peak absurdity, imo. Even K-9 can't match that era.

Where the absurdity of modern Who falls a little flat is how all the companions end up having a portion of their run basically being part of a comedy duo that tells inside jokes. They become fast friends with the doctor, and the writers have them riffing off of each other like Abbott and Costello, no matter what the rest of their personality is like. You could probably pick a more accurate comedy duo with some thought, but that's the best my tired brain can do lol.

Point being that the absurdity is sometimes shoe-horned in as a way to make it feel like the companions and the doctor have spent all the time in between episodes having other adventures. But it's off screen, so it feels forced too often.