Will PCIe x1 x4 cards work in x16 slot?

Yes, a x1 card should work in a x16 slot It's good that you've got it to work in a x1 slot What else have you tried it in besides the x16 slot

AMD Ryzen™ 7 7745HX, 8 Cores16 Threads & AMD Radeon™ 610M 2× 2280 SSD Slots PCIe X16 connector ×1

pcle slot GPUs are usually installed in the top x16 slot, as it has the most bandwidth and, traditionally, the most direct connection to the CPU Modern PCIe SSDs use

pcle x16 slot List of Motherboards with 4 PCI-Express x16 Slots: ASUS Pro WS TRX50-SAGE WIFI, GIGABYTE A620M C, GIGABYTE B650M C V2, ASUS Prime B760M-A AX, GIGABYTE B760M