Is $5k enough to start dividend investing?

5K is a good amount per transaction or per stock. Even if you want to DCA, invest every quarterly for example when you have 5k that you are willing and able to put aside.

Do note that your dividend portfolio does not comprise of only 1 stock. You will need to diversify them over the years

Using DBS Vickers Cash Upfront, I think $5k is reasonable though the best amount to put in is $8.3k. I think I would prefer to practise splitting the purchase into few different tranches as we are in this uncertain situation.

For dividend stock, I dont see the need to have any sort of frequency. Like for myself I bought DBS, I will average down at 10-20% below my buy in price.