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As already noted by another poster, OER/PfR could load balance your outbound traffic. Inbound, though, with only a /24 is problematic. As also noted by other posters, you cannot subdivide the /24 (on the Internet) and so the best you can accomplish is each ISP advertise your /24. If they do this, remote hosts will take what they believe is their best best path to your /24. So, your inbound traffic will depend on where your remote hosts are vis-a-vis your two ISPs.
In theory, your ISPs could cost or prepend your /24 higher to some of their BGP AS peers, which would influence your inbound traffic per ISP. That's "messy" and difficult to maintain, and not dynamic based on load. (Although in theory, PfR could send updates to your ISPs to indicate you want traffic shifted. Lots of luck trying to get ISP cooperation unless you have very deep pockets.)
To recap, you can pretty easily outbound load share, including dynamically with OER/PfR. For inbound load sharing, probably the best you can easily do is get each ISP to advertise your /24 "equally" to their Internet AS peers.
