How can I solve the problem of GPU encoding resolution limitation?

Environment: rtx4080ti videocodec12.0 cuda11.1 opencv

I have an 8x 4k video stream that needs to be concatenated into a super high resolution (3840 * 4, 2160 * 2) video stream with 2 rows and 4 columns for encoding and streaming. However, upon checking the matrix supported by the GPU, the maximum support for H264 encoding is 4k, and the maximum support for H265 encoding is 8k. May I ask how to break through the encoding resolution limit and perform GPU encoding on ultra high resolutions (3840 * 4, 2160 * 2) or higher, or what other methods can be used to achieve this?