Your questions -- this one and the one about extending into the garage really need to be directed to someone local.

Most things can be done with enough money and time, but no one here can see your house like someone on site.

I value professionals time and my own. With regards to this question I was hoping to elicit advice from either someone who has done this to their own home or someone who does this professionally that could speak to the feasibility before I call someone local. Your commentary is not helpful in that way. If you have a specific insight and expertise that addresses either of my questions feel free to let me know and I would be happy to learn more.

your issue is not an internet availibale solution.

I didn’t ask for a solution. I asked for suggestions and insight. If you don’t know how to answer the question in my post then don’t. The question is there for people who do. And if they don’t exist fine. But this doesn’t add any more value.

My suggestion is to ask someone local..The internet /social media is not your answer.

You’re right. What’s the point of an internet form of thousands of people seeking home repair and renovation questions other than for people like you to tell us that we should just call someone local. Thank you for enlightening me.

You are on MY post. I know how to call people locally. I sought the internet for the reason it exists. To ask the thousands of people who might have an answer. Even if it ends up being wrong. Because I’m interested and curious in crowd sourcing suggestions. Unfortunately that means attracting judgmental and rude people like you. Go offer help and advice to someone else. It’s not helpful to me. And if none of the other of thousands of people on this site have it then fine. But neither do you and there’s no reason to belabor that point on my post just because I informed you that it wasn’t helpful or in the spirit of this site.

I’ve noticed that the door frame and the timber that frames the door are likely rotting

Then show us a photo of the suspect areas. That long shot tells us nothing.

'Likely rotting' .Is it or isn't it? Easy to use a knife, pen knife/ pocket knife to check for wood rot.

If it is rotting & the damage is not extensive, look into epoxy systems to restore the wood rather than replacing. "Abatron" is one.

I don’t know if it’s rotting. Aside from the more obvious signs of age and distress there is a strange odor just in that small area that cant be attributed to anything observable. How do I use a knife to check for rotting? Here is a closer photo of the wood underneath the paint as well as the door jam where it appears it was filled with some sort of foam by the prior owner.

The frame,jamb and/or other components can be replaced while retaining old door. Skill required to do so is far more advanced than required to replace with pre-hung door.

I hope that answers your question.