My dd was born at and remains above 90th centile and at just over 4 months she is over the weight limit for her beloved bouncer.
We use it loads as she'll only tolerate lying down for short periods when awake, she likes to be more upright. I was going to get a bumbo seat but the OT at our children's centre advises against as apparently they limit the development of core muscles.
What other options are there? She can't really sit supported yet never mind unsupported, I've been propping her up on the settee but she keels over within about 30 seconds bless.