How bad is your current block? Has it already been re-bored/ can you get pistons for a re-bore? Will your head fit on a re-bore - or a new block?
You won’t get loads more power out of a 2.8 but you will take some value off your car for not having the original engine. We can argue til we’re blue about matching numbers being a “thing” but it does seem to matter to buyers. I’d have thought a good quality rebuild, balanced, etc by a decent engine chap is likely to last just as well, and provide no discernible power loss over a crate rebuild. And for similar cash…