I would say an SA (Solution Architect) is very different from an SE (Sales Engineer) in one fundamental way: the SA is focused on delivering value post-contract and the SE is focused on making sure the org is able deliver the value promised by working with sales in the pre-contract phase. In some smaller companies or organization within a company, I can see these roles being performed by the same person but in general that distinction between pre and post sales has been my lived experience.

Where I work, SAs are pretty much technical pre-sales. (There are also chief architects who are somewhat related.) If a customer needs ongoing post-contract support, they can buy a TAM (technical account manager). We don't have sales engineers.

(When I worked for a long-ago hardware company, system engineers (SEs) were pretty much the equivalent of SAs where I am currently.

SA people that I have met so far (30+) can architect and more importantly talk about and market the solution. But the execution is often times lacking. And that is solely because the execution is less important. (If the contract is big enough SA can always lean on product engineers or hire contractors to execute).

Being the engineering contractor to SA organization is daunting to a programmer, but rather rewarding.

Agreed this was my experience with the SA role