US foreign policy does not change regardless of who is the president, this should be obvious even for 5 year olds by now.
TPP will not come back because there is no popular support for it in the US, even Hillary dropped her support for it, however he will continue a policy that aims at achieving maximum damage to China/Russia through every means possible. but how can he even seriously harm China? by the time he is president in 2021 China will be even more capable than now, the Chinese semiconductor industry will be in a better position than now and the GDP may become around 16$ trillion.
So he does not have too many economic options against China, thus the US in 2021 (even if it was Trump instead of Biden) will depend mainly on non-economic ways to try to deal with China, mainly continue the freedom of navigation patrols, ramp up the sanctions on North Korea in hopes for a regime change, place more missiles in Australia, Japan and may be South Korea if they accept it, strengthen the Quad, try to convince India to host US and NATO military bases.
Almost every single US president has started some sort of a military conflict, Joe Biden himself is an absolute warhawk so it's highly unlikely that he will be one of the few exceptions that wouldn't start a war (not with China obviously because China is too much for them but with some other nation), so the question in which country Will Biden start a conflict and how is it gonna look like? a civil war may be like in Libya and Syria? a colour revolution like the one in Ukraine? Regardless the US will probably target a new country under a Biden presidency, may be regime change in Thailand or Algeria or Venezuela.