Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32u0/STM32U031/TIM3/TIM3_DCR#0x0
DBA=B_0x0, DBL=B_0x0
TIM3 DMA control register
DMA base address
0 (B_0x0): TIMx_CR1
1 (B_0x1): TIMx_CR2
2 (B_0x2): TIMx_SMCR
DMA burst length
0 (B_0x0): 1 transfer,
1 (B_0x1): 2 transfers,
2 (B_0x2): 3 transfers,
17 (B_0x11): 18 transfers.
https://github.com/modm-io/cmsis-svd-stm32