I could resolve this issue as well by patching /lib/private/Files/ObjectStore/S3ObjectTrait.php and lowering S3_UPLOAD_PART_SIZE from 512MB to 256MB.
It might make sense to make this a configuration option? I guess the optimal size here is different depending on the S3 backend used? (e.g., I’m not using AWS S3 but DigitalOcean Spaces)