There isnt anything inherently wrong with crossovers, especially if thematically the two properties connect and offer some degree of synergy. Take Helldivers and Killzone; the Helghast are an appropriately authoritarian regime that slots in perfectly with that world of managed democracy. The cosmetics offered also managed to look like something that youd find in Arrowheads bug squashing universe. And then you have Teenage Mutant Ninja Turtles arriving in Call of Duty.
Source: N4G PC Call of Duty continuing to embrace Fortnite style crossovers feels like a dilution of the brand