The general feeling on this forum is only filing I-485 AOS is showing immigration intent and must be timed correctly, so one stays inside the US on valid TN status until GC approval.
The filing of I-140 does not show immigration intent. (lots of posts on this topic on this forum). Although a few lawyers do feel this "may" show immigration intent. (incorrectly).
The buying of a home in the US does not show immigration intent. You are not required to have a residence in Canada when you are on TN status (unlike tourist B1/B2 status). The purpose of TN is to live in the US in a temporary basis (up to 3 years for each TN).
Many retired Canadians do own a second home in the US sunbelt areas (Florida, Arizona, etc) and visit the US on tourist B2 visa for up to six months, but they must maintain a primary residence in Canada to be admitted as a tourist.
From an immigration point of view, no issues with TN renewal or new TN when owning a home in the US.
I doubt you will obtain a response from someone who owned a home on TN status. We have many readers on this forum, but only a few posters.
This topic was discussed before, search the TN forum to find the responses. It is really a personal decision.
Personally, I was on TN for 2.5 years (2015 to 2018), on H1b for 1 year (2018-2019) and obtained GC in 2019. My spouse and I did not feel comfortable buying a home until we obtained our GC.
My spouse and I owned a "starter home" in Canada for several years, upgraded to a larger home for several more years, so we definitely understand the benefits of owning vs renting. We rented for four years when we moved here in 2015 and it was tough to see all that rental money go to our landlords mortgage rather than our own mortgage. But, due to the high cost of housing in Southern California and the uncertainty of the US immigration system, we waited. (side note, my H1b was initially denied due to frivolous reasons, but ultimately approved).
A general rule of thumb is you should live in your home for at least five years for it to be cost effective compared to renting. But lots of factors at play.
We bought our home in late 2019, before the pandemic hit. In hindsight, it would have been better to rent for one year 2015/2016 then buy in 2017. We would have been better off. But we only know that now with the benefit of hindsight.
It is a personal decision and you won't really know if it was a good decision until the year 2025!