Just a hypothetical - if one used a LUT on an adjustment layer above everything and then graded everything so that it looks good with the LUT and then exported a 10bit file without the LUT, could this be used as HDR output?
No. When you turn off the tonemap LUT the colours would be off because it is HDR with SDR adjustments. You would need to convert your SDR adjustments to HDR for it to work. Even then without an HDR monitor you don’t know how it’s going to look until it’s fully rendered and viewed in HDR on your TV.
Really you need to do your adjustments in HDR with a proper monitor for it to work well.