You could go with a virtual analog syntesizer. Like the Roland JD-Xa https://www.roland.com/global/categories/synthesizers/analog_modeling/ Or better a workstation like their FA series https://www.roland.com/global/products/fa_series/ (they have an analog modelling section and a sampler) or the scaled down Juno DS. https://www.roland.com/global/products/juno-ds/
Casio has some nice synthesizer but they are selling them as stage pianos, like the PX-5S https://www.casio.com/products/electronic-musical-instruments/stage-pianos/px-5s or the PX560 https://www.casio.com/products/electronic-musical-instruments/synthesizers/px-560 or the worksation mx-x 500 https://www.casio.com/products/electronic-musical-instruments/synthesizers/mz-x500 (this one has a monosynth mode, like their older XW-G1 and XW-P1 ones).
I have a PX-5S, an XW-G1 and a 1990s relic a Kawai K5000s, but I used the Rolands.
On these synths you have normally to dive into software menus to change the parameters, you could hook some knobs and sliders to adjust them, but things are becoming complicated. A true analog has a lot of knobs and is more intuitive to use.
