Here are photos

You need to give it another good pruning. It's the woody, bottom part of the plant that helps keep it standing upright. Too much long tender growth will cause it to lean over.

The flowers are finished and their stalks serve no further purpose. Clip the plants over with the shears (hedging shears, not secateurs, they're much quicker) to remove the flower stems and an inch or so of the foliage. Don't cut too deep into the foliage. Lavender doesn't regenerate well from woody stems. Clipping old flower stems is routine maintenance for lavender.

Like floral said. It's ok to leave about an inch of woody stems, when pruning for winter, isn't it? Couldn't pruning all the way to ground level, possibly damage the crown?

I watched several videos of lavender “experts” cutting pretty deeply into the wood to prevent them from getting woody too quickly. Ugh. So that is not the right thing to do?

You can cut into the wood as long as there is still foliage growth that emerges from that area. It is cutting back below any green or foliar growth that can be a problem.

IME, overly rich soils can easily cause this problem. So often planting areas that have been amended to accommodate the needs of other, fussier plants are just too rich for the likes of lavender, which really prefers a "tough love" sort of situation :-)

I agree with Gardengal -- that's how my lavender looked every year after I planted it in rich, moist clay. I ended up creating a raised "rock garden" for lavender and other herbs, and that finally fixed the problem.

I had mine growing in a very sandy bed for dry loving plants like Manfreda,Opuntia, leadplant and rattlesnake master. It did very well and gifted me with a beautiful volunteer.

I didn't say leave an inch of foliage. I said remove an inch, or so. That's erring on the side of caution but probably best for an inexperienced trimmer. You'll learn after a couple of years how low you can go.