You are asking about doing two rollovers, not one. Combining the amounts and making one deposit does not make it one rollover.
Only one of these two distributions is permitted to be rolled over. Rolling over both would be a violation of the one-rollover-per-12-months limitation and would result in an excess contribution subject to penalty. You would generally want to roll over the larger of these two distributions if you have the money. Today 02/19/2022 is generally he deadline for rolling over the the 12/21/2021 distribution if you choose to roll over that one and 03/01/2022 is the deadline to roll over the 12/31/2021 distribution.
Note that if you rolled over any other IRA distributions made in 2021, neither of these distributions is eligible for rollover. Also, if you rolled over any IRA distribution made between 12/22/2020 and 12/31/2020, the 12/21/2021 distribution is not eligible for rollover.
Note, however, if either of these distributions made in December 2021 is not eligible for rollover to a traditional IRA, they are still eligible to be rolled over to an employer plan like a 401(k) (although certainly too late to accomplish that with the 12/21/2021 distribution) or converted to a Roth IRA. If you convert to Roth, the distribution is still taxable but you'll avoid the 10% early-distribution penalty and gains in the Roth IRA will be tax free once your Roth IRAs are qualified.
