Very High-Resolution 4K Output

Gentlemen,
I am working on a slide show with very high resolutions stills, adding text, color grading and background music.
My objective is to generate the best quality (sharp and crisp images) 4K-resolution video to be played by smart-tv sets and table-top video players. File size is not a concern.
I have tried Format:MP4, Codec:H.264, Resolution:3840 x 2160 Ultra HD, Frame rate:24 but the output quality is affected by compression.
I am running the latest version of Resolve 14 in a Windows 10 environment.
I am s new to DR, still learning, and I am not familiar with other Format and Codec designations.
What other combinations of Format and Codec should I try?
Thank you for your suggestions and comments.
Persio.

Export to DNxHR, Cineform, ProRes and then convert to h264 with e.g. Handbrake.

Andrew,
Thank you for your recommendation.
Can you be more specific? What Format and Codec should I choose?
Thanks,
Persio.

Gentlemen,
I ran several informal tests and concluded that the most effective deliver configuration for my needs is as follows:

Format: QuickTime
Codec: H.264
Resolution: 3840 x 2160 Ultra HD
Frame rate: 24
Quality: Best
Key Frames: Auto; Frame reordering (selected)
Encoding Profile: High

Key findings:
Quality of well exposed and sharp images on a 65" 4K TV is excellent.
QuickTime file (.mov) is directly readable by most devices (set-top boxes and smart-tvs).
H.264 generates an acceptable file size (portability).
DaVinci Resolve 14 does an outstanding job rendering a clip with this configuration.

Happy Holidays.
Persio.

That's perfectly fine – IF it does not get re-encoded!
You must be sure that your footage stays as it is until screened. Plus, while encoding to H.264 is decent in Resolve now, there are better encoders, check the discussions here in the forum.

I'd keep a high quality archival version, though, in case you need versions in H.265 (or any other future codec). For this, DNxHR, ProRes or CineForm in their best quality would be right.

Uli,
Thank you for your comments.
I am in the Windows environment so ProRes is not an option.
I am not familiar with either DNxHR or CineForm, can you be more specific in terms of the Format and Codec I should use to generate a high quality archival file?
Thank you for your comments.
Persio.

These codecs are made for archival high quality masters (support 10/12bit 4:2:2 and 4:4:4 and any resolution).
You don't need to know anything more. Go to Resolve export and choose MOV and then DNxHR or Cineform.

The container format can be MXF or MOV, the codec for DNxHR HQX (RGB 444 might be overkill).

Cineform at the highest level is good too, but only offered in MOV.

For this type of scenario, I recommend Exporting to a .DPX Image Sequence Master file then use your favourite transcoder to create your Deliverables.