Memory card(s) for G9

I am getting several second lag when entering playback mode on my new firmware-upgraded G9. I have tried several cards. don't have this issue with my older cameras, such as G80. At the moment I am using a single card in slot 1. There are some older threads where the lag is discussed, for example:

https://www.dpreview.com/forums/thread/4331766

The most up-do-date card I am using is Kingston CANVAS React 128GB, UHS-I, V30 card. It's the older CANVAS React card, not CANVAS React plus.

Is there a way to resolve the playback lag, perhaps there are certain cards that are tested not to have this issue? I am looking for cards that cost about 50€ a piece or preferably less (if I have to I can pay more). I plan to keep a larger and slower card as a backup, so card size is not so important (two fast 32GB cards would be more than enough).

If I have a small but fast card in slot 1, and a large but slow empty card on slot 2, does the second card slow down the performance, especially when entering the playback mode? I would use the cards so that the camera records to card 1, and when it is full, it starts to record to card 2. This way I would get excellent performance in normal use while also having plenty of storage capacity, while keeping the costs low. I do video stuff and I do wildlife photography, but I don't use burst mode.

My summary about the SD Bus speeds, correct me if I am wrong:

Basic UHS-I can transfer 50MB/s. UHS-I (UHS104) can transfer 104MB/s, which is about the same as the maximum G9 can do. As G9 divides the bandwidth between the two slots, it seems that in UHS-I mode, the max transfer rate is about 50MB/s per slot. In practice it seems that this is even slower (35MB/s or so).

There are also DDR208 UHS-I cards. They should be able to transfer up to 180MB/s, It seems that the read/write speeds are only available with specific SD card readers and with G9 the speed is the same as with normal UHS-I (35MB/s or so).

The technology I am referring is explained here: https://en.wikipedia.org/wiki/SD_card#Bus