Samsung's Galaxy S20 series is among the very few smartphones in the market that can shoot 8K@24fps videos out of the box. This is an impressive feat since almost all popular DSLRs out there are also incapable of recording videos at such high resolution. However, if you plan on frequently recording 8K videos on the Galaxy S20, you will have to pay for it in terms of storage space.
As per Samsung, one minute of 8K video recorded on the Galaxy S20 will take around 600MB of space. For comparison, a minute of 4K video recorded on the Galaxy S10+ is around 350MB in size. Given that an 8K video has around 4x more pixels than 4K videos, it is impressive that 8K videos on the S20 take less than twice the amount of space as 4K videos. This is likely due to Samsung using the HEVC codec which offers greater space savings.
The base variant of all Galaxy S20 models comes with 128GB of storage, so you can record 8K videos once in a while on the device without worrying about running out of space.
Do note that there's a limit of 5 minutes per video while recording content in 8K on the Galaxy S20. This cap is there irrespective of whether you have the Snapdragon or the Exynos variant of the device. The cap is there due to processing power and thermal limitations as recording 8K videos for even a short period of time puts the device under heavy load.