Hi,
Regarding the improvements, the team is targeting some improvements to arrive when we update Twinmotion to utilize Unreal Engine 5.1 (currently expected around the end of Q1, though this may be subject to change), however these may not entirely eliminate the problem, and it may be some time before the denoiser works well enough that third party tools would be entirely unnecessary.
Right now, the third party denoisers that seem to offer the best results would be the Neat Denoiser, which is a plugin for several video editing software suites that includes a free demo version you can try. Davinci Resolve and Adobe Premiere also offer denoisers that work fairly well.
I hope that's of some help.
Best,
Raghib