You're (you and DH) over thinking it. You need a longer term view and more realistic expectations.
You seem to be writing like you are hoping to 'fix' baby to be the 6.5 month old you would like. In fact this is not separation anxiety (that's something for the 18ish month old), it is just your baby being your baby.
The normal for many babies is to need parental comfort when they wake. Especially so babies who are/were breastfed to sleep. Just because your baby needs this doesn't mean they will forever.
It's not a slippery slope to meet babies needs so they don't get distressed. You could refuse to meet baby's need for your comfort, if it is a massive big deal to you and you simply cannot give baby that comfort. But there isn't a need to
There are easy, non distressing, no crying ways to gradually teach independant sleeping. But this won't give you an independant sleeper within a month or so. But it's something you can aim towards by 12 months ish, certainly. But all means encourage independant sleep.
Having two different places to sleep is not a good idea. It means comfort comes in 'this cot' (the one in your room) and distress comes in 'this cot' ( in her room) - not a conducive method for a long term view of independant sleep.
Better would be to have a sleeping place that offers all the comfort needed, quickly and effectively. A cot in your room for example. Or you on a bed in baby's room if this is better for you both.
Then gradually reduce how much comfort you nedd to give. Start with less in-cot settling so that baby can learn to go into the cot fully awake, and gradually decrease the amount of in-cot srttling needed. But your presence is still there because the cot is next to your bed.
Then as baby gets older and towards 12 months, hopefully will start not needing feeding in the night, just in-cot settling. Then not waking at all (yay!).
Then put some distance between cot and your. Cot further down side of your bed, not eye-to-eye. Then cot at end of bed. Cot on DHs side of the bed, and so on.
Then, then cot in own room. Now that in-cot settling is established fully, night weaned and sleeping through.