"Then IBM decided to increase the cloud costs, the licensing pricing, overnight."
No - those bastards had it planned all along. They weren't making money on a lot of the contracts because IBM usually went in with loss-lead bids with the intention of selling more IBM crap or making up the money charging for project work (high cost but done by cheap labour - it was more often than not a total shit-show). The software/hardware IBM shoe-horned in (regardless of whether it was any good or not) was heavily discounted (as is the case with most big companies - no-one ever pays list price).
Of course GTS struggled to make money - it was crippled from day 1.
Post spin-off, IBM waited long enough (having novated contracts that lumbered Kyndryl with the burden of cost), they upped their prices substantially overnight. It fell to Kyndryl to either eat the cost or pass it on to the customer. Either way, Kyndryl got screwed.
The customers who didn't want to cough up the additional cost are walking away. That obviously decreases the customer base, and, depending on the size of the account, leaves people searching for other accounts to work on - they go onto the bench. You can only stay there so long.
IBM were never Kyndryl's friend (despite the rhetoric at the time).