A microSD card will always fit into any microSD slot, no matter what device you are talking about.
Are you sure you didn't accidentally insert the microSD card into the SIM card slot? Some Galaxy Tab S6 models have LTE connectivity and therefore have a slot for a SIM card. Slots for SIM card and SD card are usually in the same holder, just on opposite sides.
https://youtu.be/U1XWxqZXBd0
If you have an S8+, it shouldn't be a problem. The memory can be expanded by up to 1TB with a microSD card (see specifications).
If I'm not mistaken, the SD card slot is on the left side when you hold the tablet horizontally.
Samsung Galaxy Tab S8+ (12.40 ", 256 GB, Graphite)
It worked without problems on my Samsung S10e. Your phone is newer and I think it should work.
To be on the safe side, check here:
https://www.samsung.com/de/support/mobile-devices/welche-speicherkarte-passt-in-mein-galaxy-smartphone-tablet/
Samsung states the following: The read and write speeds quoted are based on internal tests conducted under controlled conditions. Actual speeds may vary depending on card capacity.
Try formatting again via MicroSD adapter on another device (e.g. notebook with corresponding slot or external card reader via USB on notebook / desktop) with corresponding software.
Yes, this works without any problems, MicroSD is MicroSD and they are also compatible with older smart phones, especially with a size of only 128GB there are no problems.
If you already have the feeling that something is wrong, you could at least make the effort to check. Whether the feeling is right or not. Thanks to various search engines on the internet, this is no big deal nowadays.
https://www.samsung.com/ch/memory-storage/memory-card/evo-plus-64gb-microsd-card-2021-mb-mc64ka-eu/
Do you think 130 MB/s is too fast or why do you think it's wrong?
https://kb-de.sandisk.com/app/answers/detail/a_id/22729/~/microsd%2Fmicrosdhc%2Fmicrosdxc-card-support-information-page