Secret paternity - can I still become a UK citizen?

Hi all, I have what I suspect might be a fairly complicated citizenship case. For context I was born in the late 90s in the US.

I recently discovered at 27 that the father I was raised with is not related to me, and my biological father is a British man “Tom” (who was born in the UK). Unfortunately, Tom died in 2007 and all of this is only coming out now.

Tom does, however, have a brother (also UK born) and several cousins.

If I obtain properly accredited/verified dna tests showing I’m the niece of Tom’s brother and related to the cousins, along with the test showing I’m unrelated to the father on my birth certificate, is there a possibility I could still get citizenship by descent?

I also have several people willing to give written statements confirming my mom and Tom were dating at the time of my conception, along with photographs of them together. There are a few other circumstantial things that I’m not sure would be helpful - like Tom writing a children’s book for me when I was little, the fact that I was named for his hometown, and the general home DNA kit results with strong evidence for a British father.

Overall I’m just a little lost about this whole process (especially amidst the drama of realizing all of this), so if anyone might have info on how more complicated paternity cases are handled by the home office, I’d really appreciate it. Thanks!

TL;dr : Found out my real dad was born in the UK, but he died almost a decade ago. Is it too late to “prove” my citizenship by descent if I use other close relatives?

Edit: just wanted to update this and say I’ve spoken to a UK solicitor and they’ve agreed that I have a case (whether tom’s brother agreed to a test or not, though it’ll be a stronger case if he does). So a bit of an upside to an otherwise very stressful situation!