Need help with liability minimization when transferring funds from a standard brokerage into Roth IRA

I developed a standard brokerage account and Roth IRA in Ellevest between 2020-2025 (until they transitioned their assets to Betterment). It was my first time investing, and I let the roboinvestor do the work. Then once Ellevest moved to Betterment, I was running these two accounts via the Betterment roboinvestor for about a year. I am not maxing out my IRA, and contributing about $200/mo to each account (brokerage and IRA).

I met with a flat-fee fiduciary advisor who told me I could simplify my portfolio to focus on maxing out the IRA and reduce the amount I'd lose to platform fees with Betterment by managing my portfolio myself in Vanguard, shifting all my assets into the Roth, and using an allocation of 54% VTI, 36% VXUS, 10% BND. He talked me through the process and it seemed doable to me, so I went ahead and transferred my portfolio into Vanguard.

Now I'm stumped at figuring out how to transfer the assets from the brokerage account into the Roth without triggering a sale/taxable event. There isn't a UI for this (you can transfer assets between brokerage accounts freely, though). From what I'm reading, I will have to sell the holdings from the brokerage account, keep them in a settlement fund, then deposit them into the IRA. Because it's a sale, I'll incur the capital gains tax on them.

1. Is there truly no way for me to transfer these assets to the IRA without incurring a capital gains tax?
2. Once in my IRA, can I redistribute the holdings into the allocation mentioned above without additional taxable events occurring?
3. Is there any way for me to calculate how much the capital gains will be from (1) so I can set a proper amount aside for taxes? I don't see anywhere in Vanguard that tells me how long I've had the holding to be able to estimate which bracket it'll taxed be in.

Cross-posted into [r/personalfinance](https://www.reddit.com/r/personalfinance/) and r/VanguardInvestments