I have been attempting to develop an algorithmic trading agent for a single asset pair and upon researching, it seems as if, in theory, reinforcement learning would be a natural way to approach this problem.
My idea was to have our observations be defined as follows:
$$o_i = (t_i, v_i, w_i, b_i)$$
where
$t_i$: time of observation
$v_i$: amount held by agent of asset 0
$w_i$: amount held by agent of asset 1
$b_i$: some actionable representation of the market such as quote data or order book data for an order book market, asset reserve levels for an automated market maker decentralized exchange marker, etc.
and to assume these observations are observations from a partially-observable markov decision process (described here), where the actions are defined as trading some of either asset 0 or 1 or doing nothing, so that the literature on those can be applied.
This would allow us to then implicitly model many real-world intricacies such as orders being executed before ours is executed given that we received a new observation by running our agent live and having it learn from the actual market by giving it a small amount of actual capital to work with so that it may explore and learn through actions based on the observations, perhaps pointing us more towards other insights about the market.
I am looking for what problems this approach may run into as I know I am very likely not the first to approach trading this way, e.g. this may sound good in theory, but the practical implementation is a lot more intricate, etc.