Thanks!

In order to be able to withdraw BTC, you would need to deposit some BTC in. Could be 99% - 1%... but this does mean you are paying gas on both chains. An easy way is just to LP on the RUNE side and as RUNE gains on other coins (I think this will happen in 2022) you can just slowly take profits and trade RUNE for other coins of interest.

Although, setting up an XDEFI wallet with all chains you are into is pretty easy and you could get some good LP's going that way. I am on the THORCHAIN LP UNiversity discord channel and it is full of good info and trading stategies. (ie. go into RUNE-BUSD with 100% rune on a downturn... at the bottom, withdraw more RUNE than you put in... then deposit 99% BUSD, 1% RUNE and buy the dip and gain rune all the way up... withdraw as RUNE).

I am pretty sure the APR comes from fees. I am not sure how big RUNE will be as far as THORChain mainnet will be concerned... simply being the bond / security of the network as well as every trading pair is extremely bullish for the token. Think $10 Billion in non RUNE locked on chain. That means $30 Billion in Rune is locked up on chain (Which would price RUNE at $60 is all 500,000,000 tokens are in circulation... which they are not.) That is not a lot of money to be locked up in DEFI. Once mainnet hits it should get really interesting. Financial advise... lol.