Epidemiological models feature reliable and valuable insights into the prevention and transmission of life-threatening illnesses. In this study, a novel SIR mathematical model for COVID-19 is formulated and examined. The newly developed model has been thoroughly explored through theoretical analysis and computational methods, specifically the continuous Galerkin–Petrov (cGP) scheme. The next-generation matrix approach was used to calculate the reproduction number
(
R
0
)
({R}_{0})
. Both disease-free equilibrium (DFE)
(
E
0
)
({E}^{0})
and the endemic equilibrium
(
E
⁎
)
({E}^{\ast })
points are derived for the proposed model. The stability analysis of the equilibrium points reveals that
(
E
0
)
({E}^{0})
is locally asymptotically stable when
R
0
<
1
{R}_{0}\lt 1
, while
E
⁎
{E}^{\ast }
is globally asymptotically stable when
R
0
>
1
{R}_{0}\gt 1
. We have examined the model’s local stability (LS) and global stability (GS) for endemic equilibrium
\text{ }
and DFE based on the number
(
R
0
)
({R}_{0})
. To ascertain the dominance of the parameters, we examined the sensitivity of the number
(
R
0
)
({R}_{0})
to parameters and computed sensitivity indices. Additionally, using the fourth-order Runge–Kutta (RK4) and Runge–Kutta–Fehlberg (RK45) techniques implemented in MATLAB, we determined the numerical solutions. Furthermore, the model was solved using the continuous cGP time discretization technique. We implemented a variety of schemes like cGP(2), RK4, and RK45 for the COVID-19 model and presented the numerical and graphical solutions of the model. Furthermore, we compared the results obtained using the above-mentioned schemes and observed that all results overlap with each other. The significant properties of several physical parameters under consideration were discussed. In the end, the computational analysis shows a clear image of the rise and fall in the spread of this disease over time in a specific location.