If "prepare for life after Messi" = buy young stars (Dembele, Arthur, De Jong) + elite/world class players (Dembele, Coutinho, Griezmann), then I'm pretty sure the next 2 windows will be insane as well (this one will be good unless we buy Neymar).
Get ready for Mbappe PSG --> Barca for 300M€ in 2021 for the boards election-campaign. Don't worry about finance, because are wages+budget is f***** anyway

Barto could even be stupid enough to buy De Ligt for 150M in 2021 for his candidate to get elected. It seems like we don't care about being the biggest spenders and long-term financial stability at all.
Instead of this path we should buy smarter rather than expensive proven quality.
De Jong/Arthur is smart buying. Bernardo Silva for 50M would have been. Leroy Sané for 100M this window would be smart buying.
We need to find the balance between not going Juve-style and sign free agents mostly (Ramsay/Can/Rabiot etc.), and not buying to make headlines every summer like United (we did it with Coutinho, Dembele and possibly Neymar this summer).