No chance.
Signing Messi this summer is a 400m project (100m transfer fee + 100m gross wages x 3 years).
Next summer on a free is much more likely. It would "only" be a 200m project (100m gross wages x 2 years).
Reckon Leo will play in Europe until 22-23 so he can participate in the winter 22' WC in Qatar and no longer than that.