Okay. I take it this is the team you've been using then?
https://pokepast.es/043a795349138567
I'll start by saying that my friend xx_Mythical pulled the sample teams in their answer from the video below, and while James Baek is a great player, the video is a month old. The meta has evolved and the teams might not be the most viable anymore.
https://www.youtube.com/watch?v=ltHijV6tPl8
First, I'd like to introduce you to Victory Road VGC, a great resource that compiles rental teams and team reports, often from multiple big tournaments. It's a great place to draw inspiration from when building. It's currently separated into the different restricted Pokémon, so if you'll scroll down you'll find multiple Groudon teams.
https://victoryroadvgc.com/pokemon-sword-shield-rental-vgc-teams
Second, you'll notice that many of the Groudon teams on Victory Road only have 1 sun abuser, this is generally preferred because both Venusaur and Charizard want to lead next to Groudon and Dynamax, and you're usually only bringing one or the other, making your team less flexible. Instead, using just one sun abuser allows you to support it better and more specifically. I can tell you that the best Charizard teams will look more like Elisa's team, and the best Venusaur teams will look more like Reki's team, and I'll try to explain how to beat 'Lap Dog' teams with them.
Elisa won the Women's Tour with her Groudon/Charizard team. It uses Kartana instead of Venusaur as a grass type that can KO Lapras but doesn't have to max, and Umbreon(!!), Indeedee, and Porygon2 help shut down opponents, giving Groudon opportunities to set up Swords Dances, for instance. Against Lap Dog, a good lead would be Indeedee and Porygon2. You can Follow Me + Trick Room and then use eerie impulse to shut down Lapras, and Groudon in the back can handle Zacian.
(Note that there's no linked report on Victory Road, but you can find one here:
https://www.youtube.com/watch?v=56yx3JmthiY )
Groudon/Venusaur/Thundurus/Incineroar/Celesteela is a popular core used by multiple great players (Scarf Koko is a strange choice to me, but you can put practically whatever you want in the last slot; I've seen many different late game sweepers like Urshifu and regieleki and Edu used Tapu Fini to get 3rd in the r/VGC Cup). Life Orb Venusuar in Sun can be problematic for Lap Dog, as it outspeeds and can KO Zacian (with Dynamaxed Weather Ball in sun) and Lapras, but many of these teams will use Lum Berry Landorus specifically for this, which is where Assault Vest Thundurus comes in. It takes advantage of intimidate from Landorus-T and can eat a hit from Lapras, as well as resisting fighting and steel, Zacian's most common coverage. Thundurus + Incineroar is a very good lead as you can intimidate potential Landorus and parting shot Lapras to eat hits even better, and it also helps with Amoonguss on lead. However, if they don't have Amoonguss, Venusaur + Thundurus can be a deadly lead combo too, where you either switch out Thundurus to activate Sun for Venusaur, or switch out Venusaur into Incin to get an intimidate off and potentially eat an ice move from Lapras.
Sorry for the really long-winded answer, I hope this helps :)