Kernel 7.1 RC6 (also since RC1)
(EDIT: RC7 too)
Journald complains:
manjaro kernel: virt/tdx: TDX not supported by the host platform
Means that Intel® TDX Connect is not found on a machine with AMD Ryzen 7 3700X.
That is correct, but annoying. Btw.: AMD SEV is not activated…
You may have to report this upstream if there is no patch.: https://bugzilla.kernel.org/
So they can fix it in RC7, it is more a cosmetic issue.
Immediate workaround initcall_blacklist=tdx_init in your kernel cmdline.
AMD EPYC™ Processors - Confidential Computing – Frequently Asked Questions
Is AMD SEV available on all AMD CPUs?
AMD SEV is included on AMD EPYC Server CPUs, starting with the 1st Generation AMD EPYC Server CPUs. AMD SEV is not available on 4004 and 4005 series AMD EPYC Server CPUs or AMD Ryzen™ CPUs.
means: disabled in BIOS by me. 
seems like the only viable option since it is not available for Ryzen CPUs
Does not work. If I omit “Quiet”, the message appears first (on screen).
No module tdx is loaded (lsmod -v).
In kernel exists: kernel/drivers/virt/coco/tdx-guest/tdx-guest.ko