You can use Lightning or Liquid to DCA, then, when it's economical for you, send to ColdCard. This lets you consolidate your UTXOs without paying the high on-chain fees.
Which network you chose depends on the size of the UTXO you want on-chain —Lightning is limited by the capacity on the nodes, Liquid is limited to 21 million L-BTC, the custody model you are comfortable with —single custodian (Wallet of Satoshi, Blink, Coinos,...), federated custodians (Liquid), or self-custody (Breeze, Bitkit, Phoenix,...), or signing method —software (Lightning and Liquid) or hardware (Liquid).
If that makes sense for you, you can use both.
Lightning DCA
Buy sats on Robosats, stake on Lightning, swap to on-chain. Use boltz.exchange to swap LN-BTC for BTC (0.5% fee + on-chain fees). If using coinos.io, the swap fee is (0.1% fee + transaction fee).
Liquid DCA
Use Robosats to by sats. For the payout invoice, use Boltz to create a LN-BTC to L-BTC swap (0.25% fee + LN fee). Copy the LN invoice generated by Boltz and past it into Robosats. Complete the trade.
When Boltz invoice is paid, L-BTC is automatically send to your Liquid address.
If the swap invoice expires before the trade is complete, Robosats, after 3 attempts to pay the invoice, will ask for a new invoice. Go back to Boltz and create a new swap.
Need to top up you LN balance. Use Boltz to swap some L-BTC for LN-BTC (0.1% fee + LN fee).
When it's time to send to Coldcard, go to sideswap.io/peg-in-out/ to initiate a peg out (0.1% fee + on-chain fee). Enter your BTC address, use the provided address by SideSwap to send your L-BTC.
It takes 15 to 60 minutes for the peg-out to be processed.
I recommend you read SideSwap FAQ to understand how peg-out works.
If you don't want to wait, you can use classic.coinos.io to swap your L-BTC to BTC. Create an account, send L-BTC to Coinos, send BTC to ColdCard (0.1%fee + on-chain fee).
Liquid network fee is 0.1sat/vb, so a few cents per transaction.
Unchained has an article UTXO size. I found the first table under fee protection goes beyond dust section very usfull to decide on the UTXO size.
https://unchained.com/blog/small-utxo-bitcoin-dust/
Hope this help.