On U3 (which I think you meant rather than U2), I read it as HA or MA, followed by rotated 6, and a SOT-23-6 package. A better photo might help to confirm the first letter.
One website that can help for looking up SMD part codes is
https://smd.yooneed.one/ - you start with the first two characters and then filter by package type.
Except for diodes and transistors, I've found it rarely gets you direct to the part - there is just too many options and many manufacturers use shorter codes so they can include batch info. You often need to analyse the circuit and pin connections, as well as surrounding components, to narrow down what type of device it might be. Then start looking at datasheets of potential candidates and hope the datasheet actually mentions the SMD markings. In several cases I've seen the marking information get lost in newer datasheet revisions.
Note that sometimes it isn't the first two characters that are significant, as manufacturers may use the leading characters to indicate batch or manufacturing location. More an more manufacturers do seem to be rotating these characters to help differentiate them (like the 6 on U3). Sometimes they will underline (or overline) certain characters - but you need to look at the datasheet, or the specific manufacturer part marking standards to understand what they denote. On these small parts, there is generally no indication of manufacturer, although sometime you do recognise a marking standard.