Likely increase in family income - what to do after maxing out 401k/IRAs?

My wife and I are both 32 and live in San Jose, California. We are close to having enough money to pay off her student loans whilst keeping a $15k emergency fund (about what we need for 3-4 months of living costs). I earn around $130k and she's currently looking after our baby (so no income from her). She's hoping to get back to work very soon (August), she's in a very employable field, and is likely to earn around $90-100k (based on her previous salary and what her ex-colleagues are paid). We rent and accept that home ownership is a good few years away for us ($800k+ for a 2 bedroom house here).

Student loans: $49k (currently no interest until at least the end of September).

Savings: $54k ($39k set aside to pay loans right before interest restarts and $15k for emergencies).

Investments: $32k in ETFs (mostly VT, VTI, S&P-based and sectors). All from between October 2020 and March 2021. I was a temp employee at the time, so I wanted it to be accessible (hence why I didn't use an IRA).

Retirement: $22k. I'm currently putting about 8% of my income into a 401k with a 6% employer match). Works out at $18.2k a year.

I currently allocate our spare money to go towards covering the rest of my wife's student loans ($10k more to go!). After that, I plan to put the next $12k towards maxing out our Roth IRAs for 2021.

If only I'm working then this will take all of our money for the year and early next year. However, if my wife finds a job then we'll have a lot of extra income and options on what to do with it. The plan is for her to max our her 401k (and for me to slightly increase contributions to max out mine), as well as increasing our cash savings to 6 months living costs. How else would people recommend saving the extra money and in what amounts/percentages?

1. Taxable brokerage account. One goal is to buy a house, which is unlikely to be for at least 5 years and potentially a lot more as we want to keep aggressively contributing towards retirement accounts and have a 20% down with savings to cover home ownership-related costs. Given that we have a 5-10 year time frame (if we remain in San Jose), this method appeals to me until we start getting much closer to our target amount.
2. Health Savings Account (we currently don't have one, although we do have fairly good insurance). As someone from a country with free healthcare, the thought of a ridiculous bill (even though we pay a lot for insurance...) really concerns me.
3. Add a bit more to a 529 for our daughter (10 months old, grandparents already contribute around $5k a year - half to a taxable account and half to a 529). I want to be able to put her through university without any debt, even if we have to pay some out of pocket when it comes to it. Seeing how long my wife was saddled with debt makes me want to avoid this for my daughter.

We want to end up in a situation where we have money to cover anything life throws at us, a generous retirement (maxing out IRAs and 401ks should do that), a paid off house (before retirement) and the ability for our daughter (and future kids) to go through university with no (or minimal) debt.

In summary: Pay off loans, max our 2x Roth IRAs each year, increase emergency cash fund from 3 to 6+ months, max out 401ks (x2), then what?